Calibrated to Pick your zone and the dates re-calibrate.

The Guide Crops Vol. 003

Roma Tomato

in Zone 12, this week

Determinate

Roma tomatoes, also called paste or plum tomatoes, are the ones you grow to make sauce. They differ from cherry tomatoes in an important way: a roma is a determinate plant, which means it grows to a bushy, compact size and then ripens most of its tomatoes within a few weeks, instead of giving you a handful at a time all summer. That is actually the point: you get a big batch all at once, perfect for cooking down into sauce or canning in one go. The fruit is egg-shaped, thick-walled, and meaty, with few seeds and not much juice, so it cooks down fast. Because the plant stays short, it needs a sturdy cage rather than a tall stake, and it barely needs pruning. The main thing to watch for is blossom-end rot, a dark sunken spot on the bottom of the fruit. It looks like a disease, but it is caused by uneven watering, so water steadily and mulch around the base. If you are in a cold zone (3 to 5), pick an early variety so the crop finishes before frost; in a warm zone (9 to 11) you can plant a second batch in late summer for more sauce tomatoes in fall. Roma tomatoes, also called paste or plum tomatoes, are the workhorse of the sauce and canning garden. Unlike the cherry class, roma is determinate: the plant grows to a compact, bushy size, sets most of its fruit in a few heavy clusters, and ripens that crop over a concentrated two to four week window rather than trickling out fruit all season. That concentrated set is the whole point, giving you a batch large enough to cook down into sauce, paste, or canned tomatoes in one or two sessions. The fruit is egg to plum shaped, meaty and dense, with thick walls, few seeds, and little juice, which is exactly what you want for cooking because there is less water to boil off. A determinate plant stays short enough to hold up in a sturdy cage rather than a tall stake, and it needs little to no pruning: clear the suckers below the first flower cluster and otherwise leave the plant full. The disorder roma growers fight most is blossom-end rot, a dark sunken patch on the bottom of the fruit driven by uneven calcium delivery when soil moisture swings; steady watering and mulch are the fix, not calcium sprays. In warm zones (9 to 11) a second planting extends the canning season; in short-season zones (3 to 5) choose an early paste variety so the concentrated set finishes before first frost.

Fig. 01 · Roma Tomato, mature Zone 12

Mature in

70-80d

from transplant

Sunlight

Full sun

6-8 hrs daily

Water

Regular

1-2 inches / week

Spacing

24-30"

between plants

Soil pH

6.2-6.8

slightly acidic

Today · in your zone

What's happening right now

July 24 · Zone 12 · Stage 01 · Germination

Off-season for roma tomato in zone 12.

The season at a glance

Planting calendar

In Zone 12, roma tomato grows year round here: plant in any month and harvest all year.

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

plant

harvest

indoors

plant out

harvest

Above-ground cropBest planted on a above ground moon

The season, mapped

Seed to garden

Start seeds indoors 6 to 8 weeks before your last frost date (look yours up if you don't know it, as it varies by 6 to 8 weeks across zones). When you transplant, dig a deeper hole than the pot and bury the stem right up to the lowest set of leaves, as new roots form all along the buried stem and make for a stronger, more drought-tolerant plant from the start.Start indoors 6-8 weeks before last frost. Harden off over 7-10 days before transplanting. Transplant deep: bury stem up to lowest leaves to encourage roots.

Start method

Indoors

Soil temp

70-85°F

From seed to fruit

The growing journey

Stage 01 · Germination

Germination

Days 5-10 · current stage

Tiny white root emerging from the seed, then a pale curved shoot pushing up through the soil. The shoot will straighten and the first two small leaves will unfold at the top.Tiny white root emerging from the seed, then a pale shoot pushing upward through the soil.

Tomato seeds need warm soil to sprout, about as warm as a sunny windowsill, or 75°F if you have a soil thermometer. A heating mat under your seed tray is the easiest way to get there. Cover the tray with a clear plastic lid until the first green shoots appear, then take it off.Keep soil temperature in the 70-85°F range. A heat mat makes a real difference for staying in the optimal zone. Cover with a humidity dome until sprouts appear.

FROM PLANT · Bottom heat is the single biggest factor in germination speed. If you have a heat mat, use it; if not, the top of a refrigerator or any spot that stays around 75°F works well. Most roma tomato seeds sprout in 5 to 7 days with steady warmth.Bottom heat is the single biggest factor in germination speed. A heat mat, the top of your refrigerator, or anywhere consistently warm works well. Most tomato seeds germinate in 5-7 days at 75°F.

FROM PLANT · Cover your seed tray with a plastic dome or cling wrap until the first sprout appears, then remove it immediately. The dome traps humidity to keep the seed surface moist during germination, but once the shoot emerges, that same warm, still air is the ideal environment for damping off, a fungal problem that collapses the stem at the soil line and kills the seedling overnight with no recovery. Remove the dome at first sprout and give the seedlings fresh air; slightly drier conditions at the soil surface prevent it.Cover your tray with a humidity dome or cling film until the first sprout appears, then remove it immediately. The dome holds humidity to prevent the seed surface from drying out during germination, but once the shoot emerges the same warm, still, humid air becomes the ideal environment for Pythium and Rhizoctonia, the soilborne fungi that cause damping off. Damping off collapses the stem at soil level; there is no recovery. Fresh air and slightly drier conditions at the soil surface after emergence are the primary prevention.

Seedling

Days 7-28

Two small flat leaves (the seed leaves) open first, then the first true leaves emerge between them, which will have the distinctive serrated edges and smell of tomato leaves.Two seed leaves open flat, then the first true leaves emerging between them, which will look distinctly tomato-shaped.

The moment you see the first green sprouts, take off the plastic lid covering your seed tray, as leaving it on causes a fungal problem called damping off that kills seedlings. Move the tray as close to your brightest light as you can get it. If seedlings grow tall and floppy instead of short and stocky, they need more light, not more water; that stretched-out look is called etiolation (reaching for the light), and a weak stem won't fully recover.Remove the humidity dome the moment the first sprouts appear, as waiting causes damping off. Move seedlings as close to your brightest light source as possible. Tomato seedlings require 14-16 hours of light equivalent to bright natural light to grow compact and stocky; at less than that, they etiolate (stretch toward the light) producing a weak, thin stem that never fully recovers. Leggy seedlings are almost always a light deficiency, not a watering problem.

FROM PLANT · If your seedlings are tall and thin and look weak, they need more light, not less water. Move them right next to a bright window (but pull them back a few inches at night if the window gets cold), or set up a grow light to shine on them for 14-16 hours each day. Pale color is a sign of the same problem.Leggy, stretched seedlings almost always mean not enough light, not overwatering. Get them as close to a bright window as possible, or use a grow light 14-16 hours a day.

FROM PLANT · Once you have two sets of true leaves, move the seedling into its own small pot or 3-inch cell. Tomatoes root all along their stems, so plant it a little deeper than it was sitting, as the buried stem becomes more roots.Once you have two sets of true leaves, pot up into individual cells or small 3-inch pots. Tomatoes root all along their stems, so you can bury them deeper than they were, which builds a stronger plant.

Established

Days 28-56

The stem is thicker, the plant has 3 or 4 sets of true leaves, and the color is deep green throughout. If you squeeze the stem gently it holds its shape rather than feeling floppy.Strong stem, 3-4 sets of true leaves, deep green color. Ready to pot up or transplant.

Before you move seedlings outside, you need to harden them off, meaning giving them short outdoor stints first (start with an hour or two in a sheltered spot), adding more time and sun each day over 7-10 days. Indoor-grown seedlings aren't used to wind, direct sun, or temperature swings; skipping this step shocks the plant and sets it back. When you plant, go deep: bury the stem all the way up to the lowest set of leaves. Tomatoes grow roots from buried stem, so a deeper planting gives you a bigger, more drought-tolerant root system.Begin hardening off 7-10 days before transplant: start with 1-2 hours outdoors in a sheltered spot, extending time and sun exposure each day. Indoor seedlings have thinner cuticles and underdeveloped stomatal regulation, so gradual exposure allows the plant to upregulate protective responses before full outdoor conditions. Plant deep: bury the stem up to the lowest set of leaves. Tomatoes develop adventitious roots from buried stem tissue, so a deeper planting produces a larger, more drought-resistant root system than a shallow one.

FROM PLANT · Hardening off takes 7 to 10 days and is worth every day of it. The seedlings have been raised in still indoor air with no wind or direct sun, and their leaves aren't built for outdoor conditions yet. Start with 1 to 2 hours outside in a sheltered, partly shaded spot, then add more time and more sun each day. Plants that are hardened off gradually settle in within a week of transplanting; plants that skip it can take 3 weeks to recover.Harden off over 7-10 days, a gradual introduction to outdoor conditions rather than an abrupt move. Indoors, seedlings have thin cuticles, less concentrated chlorophyll, and stomata that have never experienced wind. Sudden outdoor exposure causes sunscald, wilting, and cold stress even on mild days. Start with 1-2 hours in a sheltered, partly shaded spot, adding time and sun exposure each day. Plants that skip hardening off sulk for 2-3 weeks after transplanting while they adapt.

FROM PLANT · Plant your tomatoes deeper than the pot they came in. Dig a hole deep enough to bury the stem right up to the lowest set of leaves, as every bit of buried stem grows roots, and more roots means a stronger, more drought-tolerant plant from day one.Plant your tomatoes deeper than they sit in the pot. Bury the stem right up to the lowest set of leaves. Every bit of buried stem becomes roots.

Flowering

Days 50-80

Small bright yellow flowers appearing in clusters, each one star-shaped with petals swept back. Each flower is a potential tomato.Small yellow flowers in clusters. Each flower is a potential fruit.

When the first yellow flowers appear, change to a tomato fertilizer (those usually have more potassium, which the plant needs for fruit). Each morning, give the flowering stems a gentle shake or tap. This helps the flowers make fruit, and it really does work, especially indoors or in places without much wind.Switch from a balanced fertilizer to a high-potassium, low-nitrogen formulation. Nitrogen drives vegetative growth, which is counterproductive once flowering begins. Potassium governs sugar transport into fruit and is the limiting nutrient for fruit quality and weight at this stage. Gently tap or shake the flowering stems each morning, as tomatoes are self-fertile but require vibration to release pollen efficiently from the anther cone. In still, sheltered environments, this manual step measurably improves fruit set.

FROM PLANT · Give the flowering stems a gentle shake or tap in the morning to help with pollination. Tomato flowers release pollen when they vibrate, and bees do this naturally, but in sheltered gardens or when bee activity is low, giving the stems a quick shake does the same job. Without it, some flowers drop before setting fruit.A gentle shake or tap of the flowering stem in the morning helps pollen transfer. Tomato flowers are self-fertile, but pollen is released most efficiently by vibration: bumblebees accomplish this naturally through buzz pollination, where wing-beat frequency resonates the anthers and dislodges pollen. In sheltered gardens, polytunnels, or indoor growing environments without significant wind or bee activity, the plant depends on incidental vibration for pollination. Shaking the stem in the morning (when pollen is freshly released) is the practical substitute. Under-pollinated flowers drop without setting fruit.

FROM PLANT · Once flowers open, stop any high-nitrogen fertilizer and switch to a tomato fertilizer or one with a high third number (potassium). Nitrogen is what makes plants grow leaves, exactly right early on but exactly wrong once flowering starts. Potassium is what the plant needs to build good fruit.Stop high-nitrogen feeding when flowers appear and switch to a high-potassium, low-nitrogen feed. Nitrogen drives vegetative growth by stimulating cell division and chlorophyll synthesis, exactly what you want early in the season and exactly what you don't want once flowering starts; potassium plays a different role: it regulates stomatal opening, drives sugar transport from leaves into developing fruit, and is critical for cell wall formation in the fruit itself. A tomato-specific or high-K fertilizer (look for an NPK ratio with a high last number, such as 5-10-10 or 4-12-8) used from first flowering onward translates directly into heavier, better-flavored fruit.

Harvest

Days 70-95

Fruit is fully colored (red, orange, or yellow depending on variety) and gives slightly when you press it gently. Very ripe fruit may start to look a little less shiny than it did.Fully colored fruit that gives slightly to a gentle squeeze. The skin may start to lose its sheen when perfectly ripe.

With a determinate roma, most of the fruit ripens together over a couple of weeks, so plan to harvest the main flush in a few big pickings. Pick fruit as it colors fully red; picking promptly reduces cracking and lets you gather a batch to cook or can at once. Unlike a cherry tomato, a determinate roma will not keep pushing much new fruit after its flush, so there is no need to pick daily to keep it producing.A determinate roma ripens most of its crop within a two to four week window, so harvest the main flush in a few large pickings rather than daily. Pick at full, uniform red; prompt picking limits cracking and lets you process a batch at once. There is little benefit to picking daily to stimulate new set, as there is with an indeterminate plant, because the determinate plant tapers after its flush.

FROM PLANT · With a determinate roma, most of the fruit ripens together, so plan on a few big harvests over a couple of weeks rather than picking every day. Gather the batch as it colors up for sauce or canning.Roma is determinate, so its crop ripens in a concentrated flush; harvest the main batch in a few large pickings rather than daily. Picking ripe fruit promptly limits cracking and lets you process the batch at once.

FROM PLANT · Try a few tomatoes at different stages to find what your palate likes. Some varieties are sweetest just at peak color; others improve with a few more days. Your own taste is the best harvest guide you have.Taste as you go. Different varieties peak at different moments: some are best just before fully ripe, others need a few more days. Your palate is the best harvest indicator you have.

End of Season

Days 120-180

The plant is producing fewer new flowers, lower leaves are yellowing, and nights are regularly feeling cold. The plant is winding down.Slowing production, yellowing lower leaves, nights cooling below 50°F.

When nighttime temperatures stay below 50°F regularly, pinch off all the growing tips, the fuzzy little shoots at the ends of each stem. New flowers won't set fruit in that cold anyway (pollen stops working below about 55°F at night), and removing the tips redirects the plant's remaining energy into the tomatoes already on the vine. Bring green tomatoes inside before any frost, as they'll keep ripening on a countertop at around 60-65°F. Don't refrigerate them: cold below 50°F damages the tomato's texture and flavor permanently (this is called chilling injury).When nights drop below 50°F regularly, pinch out all the growing tips to halt new vegetative growth. Below 55°F, pollen viability declines sharply and new fruit is unlikely to set regardless of how many flowers open. Removing growing tips eliminates the hormone source (auxin from the apical meristem) that pulls resources toward new stem growth, redirecting carbohydrates into the fruit already present on the vine. Bring green tomatoes inside before frost, as they will continue ripening at 60-65°F and store far better than refrigerated tomatoes, which suffer irreversible chilling injury below 50°F.

FROM PLANT · When nights drop regularly below 50°F, pinch out the growing tips, the very top of each stem. Below 55°F, tomatoes stop setting new fruit reliably. By removing the growing tips, you redirect the plant's energy into ripening the fruit already on the vine rather than trying to grow new stems that won't produce before frost.When nights drop regularly below 50°F, pinch out all the growing tips. Below 55°F, pollen viability drops sharply and fruit set becomes unlikely even if flowers are still opening. At 50°F and below, the plant is physiologically in decline for new fruit production. Pinching the growing tips, the terminal bud at the top of each stem, removes the hormone sink that draws resources toward new vegetative growth, redirecting carbohydrates toward the fruit already on the vine. A plant with 10-15 near-ripe tomatoes will finish them faster once it has stopped trying to grow new stems.

FROM PLANT · Green tomatoes brought in before frost will ripen indoors. Lay them in a single layer somewhere cool (60 to 65°F) and dark, not the refrigerator. Refrigerator temperatures cause chilling injury, which produces the mealy, flavorless texture that makes people think they dislike tomatoes. Room temperature speeds ripening but hurts flavor; 60 to 65°F is the right balance.Green tomatoes left on the plant when frost threatens can be brought inside to ripen. Lay them in a single layer somewhere cool (60-65°F) and dark, not the refrigerator. Refrigerator temperatures (below 50°F) cause chilling injury: cell membranes in the fruit lose their selective permeability, releasing enzymes that break down cell walls, producing the mealy texture and muted flavor characteristic of cold-stored tomatoes. The damage is irreversible once it occurs. Ripening indoors at 60-65°F is slower than at room temperature but preserves flavor better than hurrying at 70°F+.

Beginner

Know your soil

Your soil

Identify yours

Not sure what soil you have? Grab a small handful of damp soil from your garden bed and squeeze it. If it crumbles apart easily, it's sandy. If it holds together but breaks when you poke it, it's loam (what most vegetables want). If it stays in a hard, slippery ball, it's clay.

What this crop wants

Roma tomatoes want soil that drains well and is rich in organic matter. If water pools on your bed after rain, or the soil stays soggy for more than a day, drainage is a problem: soggy roots rot even in otherwise good soil. The easiest fix is to work 2 to 3 inches of compost into the bed before planting, which improves drainage and fertility at once. Tomatoes are heavy feeders, so starting with rich soil means less fertilizing later. Because romas are especially prone to blossom-end rot, soil that holds moisture evenly, helped by that compost and a layer of mulch, matters even more here than for most vegetables.

If your soil doesn't match

You have sandy soil

Mix 2-3 inches of compost into the top 6 inches of your bed before planting. Compost holds moisture (which sandy soil drains too fast) and adds the nutrients sandy soil tends to lack. Repeat each season. Compost breaks down over time.

You have clay soil

Mix 2-3 inches of compost AND a few inches of coarse sand or perlite into the top 6 inches of your bed. The compost feeds the plants; the sand breaks up the clay so air and water can move through. Don't add sand without compost. It can compact like concrete.

Containers and raised beds

If amending your soil sounds like too much work, or if your soil is heavy clay, full of rocks, or contaminated, build over it. A raised bed at least 12 inches deep filled with a 50/50 mix of compost and sandy loam gives you ideal growing soil with no battles. A 5-gallon container with quality potting mix does the same for one plant at a time. Both bypass your native soil entirely.

Learn more about your soil

The specs

Care guide

The numbers that matter, at a glance.

Sunlight

Full sun · 6-8 hrs/day

Water

Regular

Spacing

24-30 inches

Soil

loam, sandy loam

Days to maturity

70-80 days from transplant

Soil pH

6.2 to 6.8

Container OK?

Yes · 5+ gal pot

Germination temp

70-85°F

Soil chemistry

Soil pH for roma tomato

Preferred

6.2 to 6.8

Tolerated

5.5 to 7

Soil pH measures acidity on a scale from 1 to 14, where 7 is neutral. Roma tomatoes do best between about 6.2 and 6.8, slightly acidic, where the nutrients they need are most available. Calcium availability matters a lot for roma in particular, because these plants are prone to blossom-end rot, which is a calcium delivery problem. Soils in the interior West (Arizona, Nevada, Utah, Colorado) often run alkaline, above 7, which can lock up nutrients even when you fertilize, so growers there often add sulfur before planting. Eastern and Midwestern soils are frequently in the right range already, but a $10 soil test from your local extension office tells you for certain.Roma tomatoes prefer a soil pH of about 6.2 to 6.8. pH governs the solubility of phosphorus, calcium, and magnesium, the three nutrients tomatoes consume in the largest quantities, and calcium availability is especially relevant for a paste type prone to blossom-end rot. Below 5.5, manganese and aluminum reach phytotoxic levels and impaired calcium uptake raises blossom-end rot risk. Above 7.0, iron and manganese deficiencies drive interveinal chlorosis on younger leaves. In the alkaline soils common across the interior West, growers routinely acidify before planting. Eastern soils often sit naturally in the preferred band; Pacific Northwest soils vary widely by parent material.

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Steady hand on the hose

Watering

When & how much

Frequency

Every 2 to 3 days in hot weather, and about once a week when it is cool. Plants drink and lose much more water when it is hot, so the soil dries out faster. Plants in containers dry out even quicker and may need checking every day in peak summer heat.Every 2-3 days during hot weather, once a week when temperatures are cool. The difference is driven by evapotranspiration rate: at air temperatures above 80-85°F, plants lose water through leaves several times faster than at 60°F, so the soil dries proportionally faster. Container-grown plants dry out faster still and may need daily checking in peak summer heat.

Amount

About 1 to 2 inches of water a week, counting rain and watering together. Water deeply enough to soak the soil down about 8 to 12 inches, where the main roots are. Deep watering pulls the roots downward, which makes the plant tougher in heat and dry spells; frequent shallow watering keeps the roots near the surface, where they dry out fast.1-2 inches of water per week total from rain plus irrigation. The goal is to wet the soil to 8-12 inches depth, deep enough to reach the main root mass and encourage roots to grow downward rather than staying near the surface. Light, shallow watering trains roots upward, making the plant more sensitive to heat and drought stress.

Method

Water at the soil, not over the top of the plant: use a soaker hose, a drip line, or just hold the hose at the base. Wet leaves are how most tomato leaf diseases get started, so keeping the leaves dry is one of the best things you can do. If you do have to water from above, do it in the morning so the leaves dry off before evening.At soil level: soaker hose, drip line, or a hose placed at the base. Wet foliage is the primary route of entry for Septoria leaf spot, early blight, and late blight: fungal spores on the soil surface travel upward in splash water, and wet leaf surfaces give spores the moisture film they need to germinate and penetrate. Morning watering, if overhead watering is unavoidable, allows foliage to dry before evening, the most disease-permissive period.

Signs of trouble

Too much water

Yellow lower leaves and cracked fruit are the two signs to watch for. Yellow leaves near the bottom of the plant mean the roots are sitting in waterlogged soil, and when the soil stays soggy, air gets squeezed out of it and the roots can't breathe. Cracked fruit usually follows a sudden heavy watering after the soil has been dry: the tomato swells fast and the skin splits. Both problems come from uneven watering, not just too much water overall.Yellow lower leaves, cracked fruit, persistently soggy soil. Yellowing lower leaves indicate roots are sitting in anaerobic (oxygen-depleted) conditions, as waterlogged soil displaces the air pores roots need to respire. Fruit cracking happens when a sudden surge of water causes rapid cell expansion in a fruit whose skin has already stopped stretching; common after heavy rain following a dry spell. Both are signs of inconsistency, not just total volume.

Too little water

Wilting during the day that bounces back overnight is the clearest sign your plant is thirsty: if it perks up after the sun goes down, water is the issue. If flowers drop before forming fruit, the plant may be under water stress: when it can't sustain fruit development, it sheds the flower at the stem (called abscission). Note that extreme heat above 90°F does the same thing, so blossom drop can happen even when you're watering regularly during a heat wave.Wilting leaves that recover overnight, blossom drop, dry cracked soil. Overnight recovery distinguishes water stress from heat stress or disease: if leaves perk up after the temperature drops, moisture is the limiting factor. Blossom drop under drought stress occurs because the plant triggers an abscission layer at the flower stem when it cannot sustain fruit development; high temperatures (above 90°F day / below 55°F night) cause the same response, so both stressors can operate simultaneously.

Feeding rhythm

Feeding

Frequency

every 2 weeks

Type

Tomato fertilizer

When to start

start when first flowers appear

When you see the first flowers opening, switch fertilizers. Use a balanced or all-purpose fertilizer early in the season, then switch to a tomato-specific or high-potassium fertilizer once flowers appear. Too much nitrogen (the first number on the package) after flowering pushes the plant to grow more leaves instead of fruit.Switch from balanced to high-potassium feed at flowering. Too much nitrogen produces leafy plants with little fruit.

N · P · K = 5-10-10

Look for three numbers on the fertilizer bag: those are the NPK ratio (nitrogen, phosphorus, potassium). For fruiting tomatoes, you want the third number to be the highest: something like 5-10-10 or 8-32-16 works well.high K, e.g. 5-10-10 or 8-32-16

Try Miracle-Gro Tomato Plant Food

Who grows well together

Companion planting

Most tomato companion advice is garden tradition rather than tested fact. The clearest exception is marigolds, which can cut down on root pests, but only when planted thickly as a cover crop a couple of months ahead, not scattered among the tomatoes. In practice: keep fennel away, keep tomatoes away from their relatives like potatoes and eggplant if disease has been a problem for you, and try nasturtiums as a trap for aphids if aphids gave you trouble in past seasons. Roma tomato companions are dominated by traditional lore with selective extension backing. The marigold/nematode connection is the best-documented pairing in this crop's companion set, effective as a dense pre-season cover crop, not as scattered concurrent interplanting. For most growers, the practical guidance is straightforward: avoid fennel, keep tomatoes away from other Solanaceae family members (potatoes, eggplant) if disease pressure is a concern in your region, and consider nasturtiums as an aphid trap crop if aphid pressure was a problem in past seasons.

Pest deterrent

Basil

A long-standing pairing. Many gardeners say basil improves tomato flavor and may keep some pests away. There is no hard proof for this exact pair, but it is widely done and harmless.Long-established pairing; flavor-improvement claims are traditional. Basil's aromatic compounds may deter some pest insects, though not extension-documented for this specific pair, but widely practiced and low risk. Traditional

concurrent

Marigolds

French marigolds can reduce root-knot pests in the soil, but only when planted thickly as a cover crop a couple of months before the tomatoes, not as a few plants tucked in alongside them.French marigolds suppress root-knot nematodes, most effectively as a dense cover crop planted 2+ months before tomatoes, not as concurrent interplanting. Extension-documented mechanism. Research-backed

Before the season

Parsley

When parsley is left to flower, the blooms draw in helpful insects that prey on garden pests. The effect is well established in general, though this exact parsley and tomato pairing has not been tested directly.Flowering umbellifers attract predatory wasps and beneficial insects; mechanism is documented in biological control literature though the specific parsley-tomato pairing is not directly extension-tested. Well-grounded

concurrent

Structural

Carrots

Carrots' deep taproot partitions the root zone differently from tomato's fibrous roots, theoretically reducing below-ground competition. This is a plausible root-zone partitioning inference, not an extension-tested pairing. Well-grounded

concurrent

Pollinator

Borage

Borage flowers attract pollinators over an extended bloom period; may also repel tomato hornworm (traditional claim). Pollinator attraction is biologically plausible; hornworm repellence is tradition. Traditional

concurrent

Trap crop

Nasturtiums

Nasturtiums function as a trap crop for aphids: aphids preferentially colonize nasturtiums, drawing them away from tomatoes. UC IPM documents trap-crop use of nasturtiums in vegetable gardens. Research-backed

concurrent

Keep apart from

Fennel Fennel releases substances that stunt the growth of many plants around it, so it is a poor neighbor for most vegetables. The trouble with tomatoes is traditional advice, but it fits fennel's known habit of holding back its neighbors.Fennel is broadly allelopathic and suppresses growth of many neighboring plants. Extension literature documents fennel as a poor companion for most vegetables; the specific tomato interaction is traditional but consistent with fennel's known allelopathic properties. Traditional

Brassicas Cabbage-family plants and tomatoes are both hungry feeders, so planting them close together makes them compete for the same nutrients. It is not harmful, but both crops produce less.Both brassicas and tomatoes are heavy feeders; close interplanting creates real competition for nitrogen, phosphorus, and potassium. Not a toxic pairing, but productivity of both crops is reduced under competition. Well-grounded

Corn Corn and tomatoes are fed on by the same caterpillar pest. Growing them side by side gives that pest more to feed on and builds up the pressure on both crops.Both crops host the tomato fruit worm / corn earworm (Helicoverpa zea, same species). Planting together creates a concentrated host reservoir that amplifies pest pressure on both crops. Research-backed

Potatoes Both are Solanaceae and share primary diseases (late blight, Phytophthora infestans; early blight, Alternaria solani) and several pests. Planting together creates a continuous host bridge that sustains inoculum across the season and into following years. Crop rotation separating Solanaceae is the standard extension recommendation for disease management. Research-backed

Eggplant Same family (Solanaceae), shares Colorado potato beetle pressure and early blight. Interplanting concentrates beetle and disease pressure; separating Solanaceae crops, even within a season, reduces crossover pest load. Research-backed

Provenance tagged inline · see methodology for the labeling system Key

Harvest signals

When to pick

Pick roma tomatoes when they are fully red all over and firm. Since you will most likely cook them, it is fine to let them ripen a little more on the vine and pick a big batch at once. A ripe roma twists off easily; if you have to tug, give it another day. Harvest in the morning when it is cooler.Pick when the fruit is fully and uniformly red and firm to the touch. Paste tomatoes are typically harvested a touch firmer than slicing types because they are destined for cooking, where dense, meaty flesh holds up. Full color indicates complete lycopene synthesis and peak flavor. The fruit should detach with a gentle twist. Because a determinate roma ripens much of its crop together, it is fine to let the fruit color up and pick in one or two large harvests for a canning batch. Harvest in the morning when cooler.

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Yield

What to expect

Expect roughly 8 to 15 pounds of tomatoes per plant, and here is the key difference from cherry tomatoes: a roma gives you most of that harvest in one big batch over a few weeks, then slows down. That is ideal if you want to make sauce all at once. If you would rather have a steady supply, plant two or three plants a couple of weeks apart so they ripen in sequence.A determinate roma typically yields about 8 to 15 pounds of fruit per plant, set as a concentrated flush over two to four weeks rather than a season-long trickle. That batched harvest is the point for sauce and canning. Once the main flush finishes, a determinate plant produces little more, so growers who want a steady supply stagger two or three plantings a few weeks apart, or add a second planting where the season allows.

A roma plant does most of its work in a short burst: the fruit sizes up green, then a large share ripens within two to four weeks. Watch for that window and be ready to cook or can when it hits.Production is front-loaded: a determinate roma ramps up quickly, peaks as most of the plant's fruit colors within a two to four week window, then tapers sharply. Plan canning or sauce-making for that peak. Your first year, expect to land in the lower part of the range while you learn what your spot needs. The four things that make the biggest difference are sun (at least 6 hours of direct sun daily), steady watering (which also prevents blossom-end rot), good soil, and catching problems early. Getting one solid batch of sauce tomatoes off a plant or two is a real first-season success.First-season plants often yield at the low end of the range as growers learn site-specific conditions. Soil organic matter, sun hours, consistent watering (the primary blossom-end-rot control), and timely disease response each move a plant within the 8 to 15 lb range. A single concentrated batch large enough to put up sauce is a genuine first-season success.

What changes yield

hours of direct sunlightconsistent watering (blossom-end rot control)feeding schedulecaging and airflow

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Pick your variety

Recommended varieties

Roma-type tomatoes, also called paste or plum tomatoes, are all grown the same way. Roma VF is the classic: widely available, disease resistant, and a great first choice. San Marzano is the famous Italian sauce tomato with deeper flavor. If blight has been a problem in your area, look for Plum Regal, which is bred to resist both early and late blight. For a pot or a small space, Window Box Roma stays compact.The roma/paste class spans classic blocky romas (Roma VF), elongated Italian sauce types (San Marzano, Super Marzano), large paste hybrids (Big Mama, Viva Italia), and heirloom plums (Amish Paste). Culture is identical across them. Roma VF carries VF (Fusarium and Verticillium) resistance; Plum Regal adds strong early and late blight resistance, valuable in humid regions. Most are determinate or semi-determinate; San Marzano runs semi-determinate to indeterminate and benefits from staking.

Roma VF

classic red paste, determinate, Fusarium and Verticillium resistant

San Marzano

elongated Italian sauce type, rich flavor, semi-determinate

Amish Paste

heirloom, large meaty plum, semi-determinate

Viva Italia

F1, productive, disease resistant

Big Mama

F1, extra-large paste

Plum Regal

F1, early, strong early and late blight resistance

Health Kick

F1, high-lycopene determinate paste

Window Box Roma

dwarf-determinate, container size

Off the vine

Storing your harvest

Room temp

About 1 to 2 weeks at room temperature, which is where tomatoes keep their best flavor. Set them stem-side down on the counter, out of direct sun, which helps them hold moisture longer.1-2 weeks at room temperature (65-70°F). Ripe tomatoes held at room temperature continue producing small amounts of ethylene, which sustains flavor development. Stem-side down reduces moisture loss through the stem scar, the most permeable point on the fruit surface.

Fridge

Try not to refrigerate ripe tomatoes. The cold turns the texture mealy and dulls the flavor, and the damage cannot be undone. If a ripe tomato would otherwise go to waste, you can refrigerate it and use it within a day or two.Avoid refrigerating ripe tomatoes. Temperatures below 50-55°F cause chilling injury: cell membranes lose their selective permeability, releasing cell-wall-degrading enzymes that produce the mealy texture and muted flavor of cold-stored tomatoes. The damage is irreversible and occurs within hours at refrigerator temperatures. If a ripe tomato must be saved from immediate waste, refrigerate and use within 1-2 days.

Freezer

You can freeze whole romas to cook with later, but do not expect to eat them fresh after thawing, since freezing makes the texture mushy. Romas are actually one of the best tomatoes to freeze because they are meaty and low in juice, so they cook down into sauce fast, and the skins slip right off once thawed.Freeze whole for cooking use; do not expect to eat thawed tomatoes fresh. Freezing ruptures cell walls, so texture turns mushy on thawing, but the skins slip off easily and the low-moisture, meaty flesh of a paste tomato makes it especially well suited to freezing and to cooking down into sauce. Blanching before freezing is optional but extends storage quality.

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When something goes wrong

Common problems

Frost or cold damage

01 of 05

What happened You'll see the leaves turn black or dark brown and go limp, sometimes overnight after a cold night. Tomatoes have no cold tolerance at all. Even without a hard freeze, temperatures below 50°F cause what's called chilling injury: the plant's cells start to break down, and young transplants are especially vulnerable because they haven't built up a protective waxy coating yet. It's tempting to think the plant just needs time to recover, but if it was hit by frost, it usually won't come back. For next time: wait until both your nighttime lows and your soil temperature are reliably above 60°F before transplanting.Tomatoes are warm-season crops with tropical origin and have no cold tolerance mechanism, unlike brassicas or root vegetables, they cannot harden or acclimate to cold. Chilling injury begins below 50°F and cell damage accelerates near freezing; a single frost event at the transplant stage usually kills the plant outright because young transplants have not yet developed the protective waxy cuticle layer that provides some buffer in established plants. Soil temperature is as important as air temperature: roots in cold soil (below 60°F) cannot take up water or nutrients efficiently even when air temperatures are acceptable, which causes transplant shock that looks like cold damage but persists for weeks after the weather improves. Next season Wait until nighttime temperatures are reliably above 50°F AND your soil is above 60°F before transplanting, checking soil temperature 2 to 3 inches deep with an inexpensive probe thermometer. In Zones 3 to 5 this often means waiting until late May or early June no matter what the calendar says.Wait until both nighttime air temperatures are reliably above 50°F and soil temperature is above 60°F before transplanting. Check soil temperature with a probe thermometer 2-3 inches deep in the actual planting bed, as a south-facing raised bed can be 10°F warmer than a shaded in-ground bed on the same day. In zones 3-5, this means waiting until late May or even early June, regardless of calendar date.

Pests or disease

02 of 05

What happened Tomato plants can run into a few common problems. Blight is a leaf disease that shows up first on the bottom leaves and spreads fastest in wet, humid weather. Blossom end rot is the black or brown sunken spot on the bottom of the tomato, it looks like a nutrient problem, but it's almost always caused by uneven watering (dry one day, soaked the next). Adding calcium won't fix it. Steady moisture will.Two of the most common problems, blight and blossom end rot, are frequently misdiagnosed and mistreated. Blight (early or late) is a fungal or oomycete disease that enters through wet leaf surfaces; spores splash up from soil and spread rapidly in warm, humid conditions, progressing from lower leaves upward. Removing affected leaves immediately slows but does not stop spread once established. Blossom end rot presents as a sunken, dark patch on the blossom end of developing fruit. Despite appearances, it is not a fungal disease and adding calcium to the soil rarely fixes it. The actual mechanism is calcium transport failure: calcium moves into developing fruit through the water stream in the xylem, and when watering is inconsistent, especially dry periods followed by heavy irrigation, the transpiration-driven flow to the blossom end is interrupted, and those cells die. Steady moisture at the root zone is the only reliable fix. Next season Water at the base of the plant (not from overhead) and stake the plant for good airflow, as leaves that dry quickly after rain are far harder for blight to infect. Move your tomatoes to a different bed each year; blight spores can persist in the soil and on old plant material. For blossom end rot: mulch heavily and water deeply and consistently rather than in small, frequent amounts.Water at the base, never overhead, to eliminate the splash route that delivers blight spores to leaves. Stake and prune for airflow, as leaves that dry quickly after rain or dew are far less vulnerable. Rotate tomatoes to a different bed each year; blight spores persist in soil and on plant debris, and a fresh location breaks the inoculum cycle. For blossom end rot: mulch heavily to buffer moisture swings, and water deeply and consistently rather than shallowly and frequently.

Too much water

03 of 05

What happened Yellow lower leaves and wilting, even when the soil is wet, are the signs you've overwatered. Soggy soil pushes out the air the roots need to breathe; once roots suffocate, the plant can't take up water even though there's plenty of it, which is why it wilts. People often respond by watering more, which makes things worse. Cracked fruit is a related but separate problem: it happens when you water heavily after a dry stretch, the tomato swells fast and the skin splits. The fix is consistency: aim for steady moisture rather than long dry spells followed by big waterings.Waterlogged soil drives out the oxygen roots need for cellular respiration, so roots in anaerobic conditions die back, and without functioning roots the plant cannot take up water or nutrients even as the soil stays wet. Yellowing lower leaves are the first visible sign, followed by generalized wilting that paradoxically looks like drought. Fruit cracking is a related but distinct problem: it happens when a sudden surge of water (heavy rain after a dry period, or a large irrigation after letting the plant get too dry) causes rapid fruit cell expansion in a skin that has already stopped stretching. The skin splits at the shoulders or develops concentric cracks. Both problems are rooted in inconsistency rather than sheer total volume, as a plant that receives consistent 1-2 inches per week rarely cracks or shows root oxygen stress. Next season Water deeply and less often rather than a little every day. Deep watering encourages roots to grow down where the soil stays more stable; roots near the surface are the first to suffocate or dry out. A 2 to 3 inch layer of mulch around the base dramatically reduces moisture swings between waterings.Water deeply and less frequently rather than a small amount every day. Deep watering (wetting the soil to 8-10 inches) encourages roots to grow down where soil moisture is more stable; shallow watering concentrates roots at the surface where they are most vulnerable to both drought and saturation. Mulching 2-3 inches around the base dramatically reduces moisture swings between waterings, which is the single most effective intervention against both fruit cracking and blossom end rot.

Not enough waterToo little water

04 of 05

What happened Flowers dropping before they form fruit and dark sunken patches on the bottom of tomatoes are the two big signs of insufficient or uneven watering. When water gets cut off during flowering, the plant sheds its flowers to conserve resources, physically cutting them loose at the stem. The dark patch on the fruit's base is called blossom end rot; it looks like a nutrient problem but it's almost always caused by uneven soil moisture, not a lack of calcium in your soil. People often add calcium supplements, but that won't fix it; steady, consistent watering will. Note that heat above 90°F causes the same flower-drop, so both can happen at the same time.Water stress during flowering triggers an abscission response: the plant activates an enzyme-driven separation layer at the base of each flower stem, dropping the flower before fruit can form. The same response is triggered by extreme heat (above 90°F daytime, below 55°F nighttime), which means during a heat wave, blossom drop can occur even if the soil seems adequately moist. During fruit development, inconsistent soil moisture is the primary cause of blossom end rot: calcium is transported to developing fruit through the transpiration stream, and interrupted water flow to the blossom end kills those cells. The external result is a sunken, darkened patch on the fruit's base. Next season Aim for 1 to 2 inches of water per week, delivered consistently. Mulch around the base with straw or shredded leaves to slow the soil from drying out. In hot climates (Zones 8 to 11), a drip line on a timer is the most reliable way to keep moisture steady without thinking about it every day.Aim for 1-2 inches of water per week delivered consistently. Mulch heavily around the base to buffer the soil against rapid drying, as a 2-3 inch layer of straw or shredded leaves can halve moisture loss on a hot day. In zones 8-11, where summer heat makes consistent moisture especially difficult, a drip system on a timer is the most reliable tool. Water at the base of the plant, never the leaves.

Not enough sun

05 of 05

What happened If your plant grows tall and leafy but produces very little fruit, or pale, flavorless tomatoes, sun is probably the problem. Tomatoes need at least 6 hours of direct sun per day; below that, the plant puts its energy into growing stems and leaves instead of fruit. What fruit does form tends to be bland because sugar development depends on sunlight. A secondary sign: shaded plants tend to stay wet longer and get more disease, because leaves don't dry out well in low light. If your spot gets 4-5 hours, you'll get some fruit, but manage expectations: fewer tomatoes, smaller, and less sweet than a full-sun plant.Tomatoes are among the most light-demanding vegetables: photosynthesis is the energy source for both vegetative growth and fruit sugar development, and fruit quality is directly proportional to the plant's photosynthetic output. Below 6 hours of direct sun, the plant redirects what energy it has toward survival, stem elongation and leaf area, rather than reproduction. Fruit set drops sharply, and what fruit does form is typically thin-skinned, pale, and bland. A secondary effect is increased disease: shaded plants stay wetter longer after rain or irrigation, and poor airflow through dense, etiolated growth creates the humid microclimate that blight and leaf mold need to establish. Next season Tomatoes need at least 6 hours of direct sun per day, and this is not negotiable. If your current spot is borderline, walk your garden at different times of day and look for a spot a few feet over that gets more morning sun before something shades it. Compact roma tomato varieties like dwarf or patio types tolerate slightly less sun than full-size plants.Tomatoes are not negotiable on sun requirements. Below 6 hours of direct sun, expect significantly reduced yields and higher disease pressure regardless of everything else done correctly. If the current spot is marginal (6-7 hours), it is worth mapping sun across the garden before committing the bed again, as a spot that gets shade from a fence or tree in the afternoon may have 2-3 more hours of morning sun available just a few feet away. Dwarf or patio-type roma tomatoes tolerate slightly less sun than full-size plants.

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The usual suspects

Pests & diseases

Pests

Aphids

P · 01

Symptoms Clusters of tiny soft green or black insects on the growing tips and the undersides of leaves, often so small they look like dots. The leaves may start to curl or feel sticky. You might see ants walking up the stems, as they farm aphids for the sweet liquid the aphids produce.Clusters of tiny soft insects on new growth and leaf undersides. Leaves curl, yellow, or become sticky with honeydew. Sooty black mold may follow. Cause Tiny soft-bodied insects that cluster on stems and the undersides of leaves. Their numbers can build up very fast in warm weather.Multiple aphid species. Populations explode rapidly in warm weather. Organic treatment Spray the colonies directly with a strong jet of water from a hose. For persistent infestations, apply insecticidal soap or neem oil spray, making sure to coat the leaf undersides where the aphids cluster.Blast off with strong water jet. Apply insecticidal soap or neem oil directly to colonies. Introduce ladybugs or lacewings. Prevention Plant marigolds or nasturtiums near your tomatoes, as both attract beneficial insects that eat aphids. Avoid over-fertilizing with high-nitrogen fertilizer, which produces the soft new growth aphids prefer.Plant marigolds and nasturtiums nearby. Avoid excess nitrogen fertilizer which creates soft, aphid-attractive growth. Encourage beneficial insects.

Tomato hornworm

P · 02

Symptoms Large sections of leaves or whole stems stripped overnight. Look for fat green caterpillars (up to 4 inches long) that blend almost perfectly into the stems, but they are easier to spot by looking for the black droppings on the leaves below.Large green caterpillars (up to 4 inches) stripping foliage. Leaves disappear rapidly. Black droppings on leaves. Cause Large green caterpillars, the larvae of a moth, that feed on leaves and stems. They show up mostly in mid to late summer.Manduca quinquemaculata moth larvae. Mid to late summer pest. Organic treatment Hand-pick and drop in soapy water, it sounds simple but it works well. If you spot any with small white oval capsules stuck to their backs, leave those ones; parasitic wasps have laid eggs on them and the wasps will do the work for you.Hand-pick, they are well camouflaged but easy to remove. Apply Bt (Bacillus thuringiensis) spray. If white cocoons visible on back, leave them, as parasitic wasps are doing the work. Prevention Till or turn your soil in autumn to destroy overwintering pupae. Planting dill or fennel nearby attracts the predatory wasps that prey on hornworms.Till soil in autumn to kill overwintering pupae. Plant dill and basil nearby to attract predatory wasps.

Flea beetles

P · 03

Symptoms Tiny round holes scattered across the leaves, especially on young plants and seedlings. If you approach the plant quickly you'll see tiny shiny black beetles jumping off the leaves: that's the flea beetle.Tiny round shot-holes in leaves, especially on seedlings and young plants. Small shiny black beetles jump when disturbed. Cause Small dark beetles that jump like fleas when disturbed and chew tiny holes in leaves. They are most active in spring on young plants.Multiple flea beetle species. Most active in spring on young plants. Organic treatment Cover seedlings with floating row cover until plants are a few inches tall and growing strongly. Diatomaceous earth dusted on and around the leaves can help; reapply after rain.Use row covers on seedlings. Apply diatomaceous earth. Neem oil spray. Prevention Transplanting larger, more established plants rather than direct-sowing reduces flea beetle damage, since seedlings are most vulnerable.Delay transplanting until plants are large. Use transplants rather than seeds.

Whiteflies

P · 04

Symptoms Tiny white moth-like insects that fly up in a little cloud when you brush the plant, clustered on the undersides of the leaves. Leaves may yellow, and a sticky coating (honeydew) can develop, sometimes followed by black sooty mold. Whiteflies are worst in warm regions and on greenhouse or container plants.Clouds of tiny white insects on leaf undersides that flush up when disturbed. Yellowing leaves, honeydew, and sooty mold in heavy infestations. Most severe in warm regions, greenhouses, and on container plants. Cause Small white flying insects that suck sap from the leaves. They multiply fast in warm weather and can spread plant viruses.Several species (greenhouse whitefly, silverleaf/sweetpotato whitefly). Populations build rapidly in warm weather, and some species transmit plant viruses. Organic treatment Spray the undersides of the leaves with insecticidal soap or neem oil, repeating every 5 to 7 days because the eggs keep hatching. Yellow sticky traps catch the adults, and a strong jet of water knocks many off. Remove heavily infested lower leaves.Insecticidal soap or neem oil on leaf undersides, repeated every 5 to 7 days to catch newly hatched nymphs. Yellow sticky traps for adults. Conserve natural enemies (Encarsia wasps, ladybugs). Remove heavily infested foliage. Prevention Check new transplants before you buy them, since whiteflies often arrive on nursery plants. Reflective (silver) mulch confuses them, and keeping plants healthy without over-feeding nitrogen reduces the soft growth they prefer.Inspect transplants before introducing them. Reflective mulch deters colonization. Avoid excess nitrogen. Monitor leaf undersides early in warm weather.

Diseases

Early blight

D · 01

Symptoms Dark brown spots on the lower leaves, often with rings inside them like a target pattern. The leaves around the spots turn yellow, then the whole leaf dies and drops. The pattern starts at the bottom of the plant and moves upward.Dark brown spots with concentric rings on lower leaves first. Affected leaves yellow and drop. Spreads upward through plant. Cause A fungus that causes dark spots on the lower, older leaves first. It spreads in warm, wet weather, so keep the leaves as dry as you can.Alternaria fungus. Favored by warm wet conditions. Organic treatment Remove and throw away (do not compost) any affected leaves as soon as you spot them. Mulch the soil around the base of the plant to stop rain from splashing soil and fungal spores up onto the lower leaves.Remove affected leaves immediately. Apply copper-based fungicide preventively. Mulch soil to prevent splash-up. Prevention Rotate your tomatoes, avoiding the same spot for at least 3 years. Water at the base of the plant rather than from overhead, and stake the plant to keep the foliage off the ground.Rotate tomatoes every 3-4 years. Water at soil level. Space plants for airflow. Stake to keep foliage off ground.

Blossom end rot

D · 02

Symptoms Dark, sunken, leathery patches on the bottom of the fruit, the end where the flower was attached. Roma and other paste tomatoes are especially prone to it, and it usually shows up on the first fruits of the season. It is not contagious and does not spread between plants.Dark, sunken, leathery patch at the blossom (bottom) end of the fruit, affecting the earliest fruit most. Paste and roma types are notably susceptible. Not contagious. Cause A dark, sunken patch on the bottom of the fruit. It is not a pest or a disease: the fruit cannot get enough calcium, almost always because watering has been uneven. Romas get it more than most tomatoes because they set a heavy crop of dense fruit all at once. Water steadily to prevent it.Localized calcium deficiency in the developing fruit, driven by uneven soil moisture or root damage rather than a true soil calcium shortage in most gardens. Roma and paste types are especially prone because their dense, blocky fruit and heavy, near-simultaneous fruit load outpace calcium delivery to the fruit's far (blossom) end. Organic treatment The fix is consistent watering, not calcium supplements. Mulch around the base so the soil holds moisture evenly, and water on a regular schedule rather than in big irregular bursts. Remove affected fruit, since they will not recover. With a determinate roma, steady moisture through the concentrated fruit set is the key window.Mulch to maintain even soil moisture. Water consistently. Foliar calcium spray provides some relief. Remove affected fruit. Prevention Water consistently and deeply, since the most common trigger is irregular watering during fruit development, which for a determinate roma is a short, heavy window. Mulch to buffer soil moisture, avoid disturbing the roots by cultivating too close, and do not over-fertilize with nitrogen, which pushes fast growth the plant cannot supply calcium to. Choosing a variety and watering steadily matter more than any calcium product.Consistent soil moisture is the primary prevention, especially through the concentrated fruit set of a determinate plant; mulch heavily to buffer moisture swings. Avoid root disturbance and excess nitrogen. Soil calcium is rarely the limiting factor, so foliar calcium sprays give only marginal relief.

Septoria leaf spot

D · 03

Symptoms Small circular spots on the leaves, with tan or pale gray centers with dark brown borders, often with a faint yellow halo around the outside. They start on the lower leaves and move upward. Not as aggressive as early blight but disfiguring.Small circular spots with dark borders and pale gray centers, starting on lower leaves. Spots may have yellow halos. Cause A common fungus that makes many small, round spots on the leaves. It spreads in wet conditions, so water at the soil and keep the leaves dry.Septoria lycopersici fungus. One of the most common tomato diseases. Organic treatment Remove affected leaves immediately. Apply copper-based fungicide if the problem is spreading. Improve airflow by staking or caging so leaves aren't touching each other.Remove affected leaves. Apply copper fungicide. Ensure good air circulation. Prevention Water at the soil level rather than overhead. Mulch to prevent soil splash. Rotate tomatoes to a different bed each year.Rotate crops. Water at soil level. Mulch around plants.

Late blight

D · 04

Symptoms Large, irregularly shaped brown patches that look water-soaked and spread fast, days not weeks. In humid weather you may see white fuzzy growth on the undersides of affected leaves. This one is serious; it can kill a healthy plant in a week.Water-soaked, rapidly expanding brown patches on leaves and stems. White fuzzy growth on undersides in humid conditions. Can destroy plants in days. Cause A fast-moving disease that can collapse a plant within days in cool, wet weather. Remove and throw away affected plants right away so it does not spread.Phytophthora infestans oomycete. The same pathogen that caused the Irish potato famine. Spreads rapidly in cool wet weather. Organic treatment Remove and destroy all affected plant material immediately, bag it and throw it in the trash, do not compost it. Apply copper-based fungicide preventively if you see it starting in your area and conditions are wet.Remove and destroy all affected material immediately, do not compost. Apply copper fungicide preventively in wet conditions. Prevention Choose disease-resistant varieties whenever possible. Stake for good airflow. Never leave tomato plant debris in the garden over winter, clear it all out at season's end.Plant resistant varieties. Ensure excellent airflow. Never leave tomato debris in the garden over winter.

Fusarium and Verticillium wilt

D · 05

Symptoms The plant wilts during the day and may recover at night at first, then wilts for good. It often starts on one side of the plant or one branch. Lower leaves yellow, sometimes in a V-shaped patch, and the plant slowly declines. If you slice the main stem near the base, you may see brown streaks inside. There is no cure once a plant is infected.Progressive wilting, often one-sided or one-branch first, yellowing of lower leaves sometimes in a V-shaped pattern, and browning of the vascular tissue visible when the stem is sliced. Plants decline and die with no recovery once infected. Fusarium favors warm soils and Verticillium cooler soils, so together they cover a wide range of conditions. Cause Fungi that live in the soil and clog the plant's water pipes from the inside, so the plant wilts and dies. They stay in the soil for years, which is why rotation and resistant varieties matter.Soilborne fungi Fusarium oxysporum f. sp. lycopersici and Verticillium dahliae/albo-atrum that invade the roots and plug the water-conducting xylem. They persist in soil for years. Organic treatment There is no spray that cures these soil fungi. Pull and throw away (do not compost) infected plants to reduce spread. The real solution is prevention: next year plant a resistant variety and rotate to a new spot.No effective curative treatment for the home gardener. Remove and destroy infected plants; do not compost. Management is preventive: resistant cultivars and rotation. Prevention Choose resistant varieties. Look for the letters V and F on the label or plant tag (for example Roma VF), which mean the variety resists Verticillium and Fusarium wilt. Rotate tomatoes away from where any nightshade grew for at least 3 years, and clean up plant debris at season's end.Plant resistant cultivars (the V and F in a VFN code denote Verticillium and Fusarium resistance; Roma VF is a common resistant paste variety). Rotate out of Solanaceae for 3 or more years, sanitize tools, and remove crop debris. Grafting onto resistant rootstock is an option for repeated problems.

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Seasoned

Where to plant next year

Crop rotation

Move your tomatoes to a different part of the garden each year, and don't come back to the same spot for at least 3 years. Soil diseases, including the wilts and blights that affect tomatoes, can survive in the soil or on old plant debris for multiple seasons. Rotation is the main tool home gardeners have to keep these in check. The same rule applies to peppers, eggplant, and potatoes: they share the same diseases, so avoid planting any of them where tomatoes grew recently.Rotate nightshades to a fresh bed every 3 years minimum. Soilborne pathogens, particularly Fusarium wilt (Fusarium oxysporum f. sp. lycopersici), Verticillium wilt, and early blight (Alternaria solani), can persist in soil or on plant debris for multiple seasons. Fusarium and Verticillium are soil-systemic and resistant to most home-garden interventions once established; the primary management tool for the home gardener is rotation combined with resistant varieties. Avoid planting tomatoes after any Solanaceae crop (peppers, eggplant, potatoes), as these share the same pathogen suite.

Family

Nightshade family (Solanaceae)

Years between

3 years

in the same bed

Avoid following

Do not plant roma tomatoes where you grew tomatoes, peppers, eggplant, or potatoes last year. These plants are all in the same family and share the same soil diseases, which can build up and carry over to the next crop.Tomatoes, peppers, eggplant, potatoes, all share blight and fusarium diseases

Plant after

Brassicas, legumes, corn, root vegetables

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In the app · pre-launch

When plant taps you on the shoulder

The plant app sends a timely reminder at every critical moment of your roma tomato season. The wording adjusts to whichever you pick: beginner or seasoned. Here are three you'll see in Zone 12.

plant

6 weeks before last frost

Time to start your tomato seeds indoors

Your last frost date is about 6 weeks away, now is the right window to start tomato seeds. Fill small trays or cells with seed-starting mix, plant one or two seeds per cell about a quarter inch deep, and put them somewhere warm (70 to 80°F is ideal). Cover with a plastic dome or cling wrap until you see sprouts, then remove it right away. This is where your season begins.

plant

10 days before last frost

Start introducing your tomatoes to the outdoors

Your last frost is 10 days away, time to start hardening off your seedlings. Put them outside for a couple of hours in a sheltered, partly shaded spot today, then bring them back in. Add more time and more direct sun each day over the next week or two. This gradual transition helps them adapt to wind, sun, and temperature swings before they go out for good.

plant

Last frost arrives

Frost has passed, your tomatoes are ready to go out

Now is the time to transplant. Dig a hole deeper than the pot and bury the stem right up to the lowest set of leaves, as roots form all along the buried stem and make for a stronger plant. Water well, and if the weather is still cool, wait for nighttime temps to be consistently above 50°F before planting out.

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Methodology & sources

Every date, temperature, spacing, and recommendation on this page is sourced from university cooperative extension publications, peer-reviewed agricultural research, NOAA climate data, and direct extension calendars. Where claims are softer (traditional gardening wisdom not formally documented), we say so.

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Traditional Time-tested gardening wisdom, limited formal research support

Last reviewed

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