Beginner Seasoned
Pick your zone and the dates re-calibrate.
The Guide Crops Vol. 003

Spring Onion / Scallion

in Zone 9, this week

A spring onion, also called a scallion or green onion, is a young onion you eat whole: the long white base and the green tops. You harvest it before it makes a round bulb, so it grows fast and is easy. Some kinds (called bunching onions) never make a bulb at all, and you can also just sow regular onions close together and pull them young as scallions. Plant the seeds shallow, thin the seedlings to about an inch apart, keep the soil damp, and they are usually ready in about 50 to 70 days, when the green tops are 6 to 8 inches tall. They handle cold well, so plant a short row every couple of weeks through the cool season for a steady supply, and nearly year-round where winters are mild. Spring onion, or scallion, is a fast cool-season allium grown for its slender white shank and green tops rather than a mature bulb. It is harvested young, before bulbing, so the day-length trigger that governs bulb onions is irrelevant here: you pull the plant while it is still a straight stem. Two routes give the same kitchen result, true bunching types (Allium fistulosum) that never form a bulb, or regular bulb onions (Allium cepa) sown thickly and pulled at the green stage. Sow seed shallowly, thin to about an inch, keep the soil evenly moist, and harvest in roughly 50 to 70 days when the tops stand 6 to 8 inches. Because the crop is quick and very cold hardy, sow a short row every two to three weeks through the cool season for a steady supply, year-round in mild regions.

Spring Onion / Scallion mature plant
Fig. 01 · Spring Onion / Scallion, mature Zone 9
Mature in
50-70d
from transplant
Sunlight
Full sun to partial shade
5-8 hrs daily
Water
Consistent
Spacing
1 to 2 in
between plants
Soil pH
6-7
slightly acidic
Today · in your zone

What's happening right now

October 21 · Zone 9 · Stage 01 · Germination & Emergence

Off-season for spring onion / scallion in zone 9.

Seasoned
Microclimate · Zone 9a vs 9b

Your zone, at a finer grain

Zone 9 averages a last frost around March 1. Within Zone 9, the colder half (9a, winters down to 20°F) runs about a week later. The warmer half (9b, winters down to 25°F) runs about a week earlier. The plant app picks your subzone from your ZIP.

SubzoneLast springFirst fallGrowing daysWinter minFruits reliably
9aMar 8Nov 24~26120-25°FYes · two seasons
9bFeb 28Nov 30~27525-30°FYes · two seasons

Averages from 8 weather stations per subzone, drawn from NOAA 1991-2020 Climate Normals. Your actual frost date can vary by up to two weeks based on elevation, proximity to water, and local topography.

Source: NOAA 1991-2020 Climate Normals Methodology
Your climate region in Zone 9
The season at a glance

Planting calendar

In Zone 9, spring onion / scallion can be planted January through May, then again August through November, skipping the summer heat. Harvest runs March through December.

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
plant
plant
plant
plant
plant
plant
too hot
too hot
plant
plant
plant
plant
too late
harvest
harvest
harvest
harvest
harvest
harvest
harvest
indoors
plant out
harvest
Seasoned
Stagger your sowings

Succession planting

Instead of planting all your scallions at once, sow a short row every couple of weeks. That way they are ready a few at a time over many weeks. In places with cool summers, plant spring through fall. In hot places, grow them fall through spring and skip the summer heat. Where winters are mild, you can plant nearly all year.Scallions are a natural succession crop: sow a short row every two to three weeks through the cool season rather than one big planting, so they mature in sequence and none over-mature. In cool-summer regions that means spring through fall; in hot-summer regions it means fall through spring, skipping peak summer heat; in mild regions it runs nearly year-round. The number of sowings is set by the length of your cool window, not a fixed cap.

Every 2 weeks · sow a short new rowUp to 12 sowings a seasonToo hot to sow midsummer
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
sow
harvest
keep sowing
too hot
continuous harvest
The season, mapped

Seed to garden

There are three easy ways. The simplest is to sow seed right in the garden, a quarter to a half inch deep, then thin the seedlings to about one per inch. Or start seeds indoors about four weeks before planting out for an earlier harvest, then set the little plants an inch apart. The tidiest way is to multisow: drop a small pinch of about six to ten seeds into each cell, let them grow as a little clump, and plant the whole clump out without splitting it, about four to six inches from the next one. Because you eat scallions in bunches anyway, there is nothing to thin, and you just pull the biggest few from each clump and let the rest keep growing. Bunching kinds can also be split from an existing clump.Three easy routes. Direct-sow seed in a two-inch-wide band, a quarter to a half inch deep, in rows 12 to 18 inches apart, then thin to about one plant per inch (UMN); this is the simplest method and suits succession sowing. Or start seed indoors about four weeks before set-out for an earlier first cutting, transplanting seedlings an inch apart. The tidiest indoor route is to multisow: sow a pinch of about six to ten seeds per cell, grow the cluster on undivided, and set the whole clump out without separating it, spacing clumps four to six inches apart; scallions are pulled as a bunch, so there is no thinning, and you take the biggest from each clump first and let the rest size up (RHS). Bunching types can also be multiplied by dividing established clumps.

  1. 01
    Sow outside
    Aug - Sep, Dec - Apr
  2. 02
    First harvest
    From Mar 1
    50-70 days from sowing
Start method
Both
Soil temp
50-75°F
From seed to fruit

The growing journey

Stage 01 · Germination & Emergence
01
Germination & Emergence
Days 7-21 · current stage
Look for thin, grass-like shoots coming up, each starting bent over in a little loop like a hairpin, then standing straight. Scallions sprout slowly and not all at once, so do not worry if they come up over a week or two.Thin, looped seed leaves push up bent like a hairpin, then straighten into the first slender tubes. Alliums germinate slowly and unevenly over a wide soil range (about 50 to 75 °F), so a sparse, gradual stand over a week or two is normal.
Keep the top of the soil damp so the tiny seeds do not dry out while sprouting, and pull weeds early, because young scallions lose out to weeds easily. If you planted young plants instead of seeds, you can skip this stage.Keep the surface evenly moist so the fine seed never dries mid-germination, and keep the bed weed-free from the start; allium seedlings are weak competitors. If you set transplants instead, this stage is already behind you.
FROM PLANT · Plant scallion seeds shallow, a quarter to a half inch deep, in a little two-inch-wide band, and keep the soil damp until they sprout.Sow scallion seed shallowly, a quarter to a half inch deep, in a two-inch-wide band so the seedlings support each other, and keep the surface evenly moist until they emerge (UMN).
02
Leaf Development
Days 21-45
The plants grow more and more upright green leaves, and the white bottom gets longer and a little thicker. Steady growth now is what makes nice tender scallions, so keep them watered and weeded.Upright tubular leaves stack up one after another and the white shank lengthens and slowly thickens. Steady, uninterrupted growth here is what makes tender, full-flavored tops; a drought or weed check thins and toughens them.
Thin the seedlings to about one per inch so they are not crowded, keep the soil evenly moist, and pull weeds. If the soil is poor, a little fertilizer helps.Thin to about one plant per inch before the seedlings crowd, hold moisture steady, and stay on top of weeds. A light side-dress of nitrogen helps lean soil.
FROM PLANT · Thin the little seedlings to about one per inch after they come up. Crowded scallions stay skinny, so give them room.Thin seedlings to about one plant per inch once they are up; crowded scallions stay thin and tough, while thinned plants make clean, pencil-thick shanks.
03
Established
Days 40-60
Strong upright tops about 6 inches or taller, with a white bottom about as thick as a pencil. Bunching kinds make a little clump of several stems. They are getting close to ready.Sturdy upright tops 6 inches and taller with a clean, pencil-thick white shank. Bunching types form a clump of several shoots; the planting is approaching usable size and will hold a while in cool weather.
Keep watering, and start pulling the biggest ones as you need them, which gives the others room. Sow your next short row now for a steady supply.Keep moisture even and begin pulling the largest plants as you need them; harvesting thins the stand and lets the rest size up. Sow the next short succession now if you have not.
FROM PLANT · Plant a short new row every couple of weeks instead of all at once, so you get scallions a few at a time over many weeks.Sow a short row every two to three weeks through the cool season instead of one big planting, so scallions mature in sequence and none over-mature waiting to be pulled.
04
Harvest
Days 50-75
Green tops 6 to 8 inches tall and a white bottom about as thick as a pencil, still straight with no round bulb. Pick them before a bulb forms or before they shoot up a flower stalk in heat.Tops 6 to 8 inches, shank pencil-thick to about half an inch, base still straight and unswollen. Pull or cut before a bulb forms and before summer heat or long-held plants push a hollow flower stalk.
Pull the whole plant, or with bunching kinds cut the tops about an inch above the soil so they grow back. Younger is milder, and do not let them get old and woody.Lift whole plants, or cut bunching types about an inch above the crown to let them regrow. Harvest on the young side for mildness; do not let plants over-mature or bolt.
FROM PLANT · Pick scallions when the green tops are 6 to 8 inches tall. Pull the whole plant, or with bunching kinds cut the tops about an inch above the soil so they grow back.Harvest scallions when the tops reach 6 to 8 inches; lift whole plants, or cut bunching types about an inch above the crown to let them regrow for a second cutting (Clemson).
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

Scallions like loose, rich, well-drained soil. Mix in compost before you plant. They do not do well in heavy clay or in soil that crusts over, because their roots stay shallow and need air and steady moisture near the surface.

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 to partial shade · 5-8 hrs/day
Water
consistent
Spacing
1 to 2 inches
Soil
loam, sandy loam
Days to maturity
50-70 days from transplant
Soil pH
6 to 7
Container OK?
Yes · 1+ gal pot
Germination temp
50-75°F
In a pot

Yes, 1 gallon and up

Scallions are excellent in pots because their roots stay shallow. Use a wide container at least 6 inches deep with drainage holes, sow or set them about an inch apart, and you can keep cutting bunching types for weeks. Pots dry out fast, so check the soil often.Scallions are shallow-rooted and ideal for containers. A wide, well-drained pot at least 6 inches deep holds a dense stand sown about an inch apart. Containers dry fast, so water before the surface crusts and feed lightly every few weeks; bunching types regrow after cutting for repeat harvests.

Pot size
1 gallon and up; 2 gallons is comfortable
Drainage
Drainage holes are a must. Skip the gravel layer. After you water, pour out any water that collects in the saucer under the pot. Scallions should not sit in standing water, because soggy soil leads to rot.Drainage holes are a must. Skip the gravel layer. Empty the saucer after watering; scallions should never sit in standing water, which saturates the shallow root zone and invites rot.
Watering
Water container scallions more often than garden ones. The soil in a pot dries out fast, and dry spells make the tops thin and tough.Expect to water more frequently than in-ground; the shallow root zone in a pot dries quickly and any drought check thins the tops.
Depth and shape
At least 6 inches deep. wide_and_shallow_ok
Self-watering pot
Yes. Self-watering containers suit scallions well, smoothing out the steady moisture they need; keep the mix free-draining so the root zone never stays saturated.
Mix
A free-draining potting mix blended with compost. Work in compost for fertility and a little balanced feed at planting.
Feeding
Frequent watering leaches nutrients, so feed container scallions lightly but regularly through leaf growth.
Winter

Bunching types are very cold hardy, so where winters are mild you can leave a pot of scallions out over winter and keep cutting. In cold areas, move the pot to a sheltered spot or mulch it during hard freezes, since roots in a container get colder than roots in the ground.Cold-hardy bunching types overwinter readily in containers in mild zones for cut-and-come-again use; in colder zones shelter or mulch pots through hard freezes, since container roots chill faster than open ground.

Pot safety

Ask what your balcony or roof can carry

A balcony or roof can only hold so much weight. Before you set heavy pots there, ask a building architect what it can safely carry.Illinois Extension's guidance is to consult a building architect about weight limits before placing heavy pots on a balcony or rooftop garden. It gives no weight figure.

Never grow food in a container with anything toxic in it

Many kinds of containers can be used. Whatever you choose, keep anything toxic out of it, especially if you are growing food.Colorado State accepts nearly any container material but warns against using a container that holds toxic materials, especially for edible plants. Illinois adds that a vegetable container should be free of chemicals toxic to plants or people, and urges caution with treated lumber when growing food. If you cannot account for what a repurposed container once held, that alone is a reason to keep food out of it.

Secure hanging containers well

Fasten hanging baskets and window or rail boxes securely. Think about what is below them too, since they can drip on people or things underneath.Illinois Extension asks growers to secure hanging containers well and to think through the safety issues of hanging them. Placement matters too, since a hanging container can drip onto people or belongings below.

Soil chemistry

Soil pH for spring onion / scallion

Preferred
6 to 7
Tolerated
6 to 7.5

Scallions like soil close to neutral, about pH 6.0 to 7.0. Clemson lists an ideal of 6.2 to 6.5. They do not like sour (acidic) soil; a simple soil test takes the guesswork out of it.Scallions grow best near neutral, roughly pH 6.0 to 7.0, with Clemson giving an ideal band of 6.2 to 6.5. They tolerate up to about 7.5 and dislike acid soil; confirm with a soil test before adjusting.

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Steady hand on the hose

Watering

When & how much
Frequency
Water scallions so the soil stays evenly moist the whole time they grow. Their roots are shallow, so dry spells slow them down and make the tops tough. If it does not rain about an inch a week, give the bed a good soak once a week.Keep the soil consistently moist through the whole short crop; scallions have small, shallow roots and any drought check slows growth and toughens the tops. If rain does not supply about an inch a week, soak the bed thoroughly once a week.
Amount
About an inch of water a week is a good target, and more in hot, dry weather. Steady is better than a flood one week and nothing the next.Aim for roughly an inch of water per week from rain plus irrigation, more in heat or sandy soil, delivered steadily rather than in swings.
Method
Water the soil at the base of the plants, not over the leaves. Keeping the tops dry helps prevent disease.Water at the base with drip or a soaker to keep the foliage dry; wet tops invite leaf and neck diseases.
Signs of trouble
Too much water
If the soil stays soggy and the bottoms of the plants turn yellow and soft, that is too much water. Sitting in wet soil makes scallions rot.Waterlogged soil and yellowing, mushy bases signal overwatering; standing moisture around the shank encourages basal and neck rots.
Too little water
Wilting, bluish, or brown-tipped leaves mean the scallions are too dry. Plants that do not get enough water stay thin and taste sharper.Bluish, wilting, or tip-burned leaves and stalled growth indicate the plants are short of water; under-watered scallions stay thin and turn sharply pungent.
Feeding rhythm

Feeding

Frequency
Light feeding during leaf growth
Type
Balanced, moderate nitrogen
When to start
Work in compost or a balanced feed before planting, then side-dress lightly as the tops grow

Scallions do not need much feeding. Mix some compost or a balanced fertilizer into the soil before you plant, then give a light feeding once or twice while the tops are growing if the soil is poor. Do not overdo the nitrogen, or you get floppy, weak tops.Scallions are light-to-moderate feeders. Unlike bulb onions there is no bulb to size, so feeding aims only at steady, tender leaf growth. Mix a balanced fertilizer into the bed before sowing, around 9 pounds of 10-10-10 per 1,000 square feet per Clemson, and side-dress lightly once or twice during leaf growth if the soil is lean. Avoid heavy nitrogen, which makes floppy, disease-prone tops.

N · P · K = 10-10-10

Mix a balanced fertilizer into the soil before planting; feed lightly later only if the plants look pale or slow.A balanced feed worked in before planting carries scallions through; side-dress lightly only if growth stalls.

Try compost plus a balanced 10-10-10 vegetable fertilizer
Who grows well together

Companion planting

Scallions are good neighbors for carrots, beets, lettuce, and cabbage-family plants, mostly because their strong smell is thought to keep some pests away, and they are small enough to slip between other crops. The main thing to avoid is planting them next to beans or peas, since onions can slow those down. These are helpful traditions, not sure things, so do not worry if your garden does a little differently. Scallions earn their companion reputation mostly through their allium scent, traditionally credited with deterring aphids and the carrot rust fly, so they pair well with carrots, beets, lettuce, and brassicas, and tuck neatly between slower crops. The one firm caution is the legume conflict: alliums are widely held to inhibit beans and peas, so keep scallions away from them. Most of these claims are traditional rather than trial-proven; treat them as low-risk suggestions, not guarantees.

Other
Carrots
Scallions and carrots are a classic garden pair. Their strong smell is said to help hide carrots from the carrot rust fly, and the two plants do not crowd each other's roots.Carrots and scallions are the textbook reciprocal pairing. Your scallions' sulfur scent helps mask the carrots from the carrot rust fly, and in return carrots interplanted with scallions tend to carry less scallion thrips damage, so each crop disrupts the other's main pest. Intercropping trials have measured real reductions in carrot fly where the two grow together. Plant in alternating rows with enough scallion density for the scent-masking to register, and note the strongest results come from small mixed plantings rather than large solid blocks. Research-backed
Beets
Beets and scallions grow well side by side. They like the same cool weather and stay out of each other's way.Beets and scallions share a bed comfortably. The onion's pungency helps deter pests that bother beets, and because scallions shank shallowly with sparse upright foliage while beets put their energy into a single root, the two do not crowd each other above or below ground. This is mostly a good-neighbor, efficient-space pairing with a modest pest-repel bonus. Traditional
Lettuce
Fast little lettuce plants fit nicely in the gaps between scallions and like the same cool season, so you get two crops from one spot.Lettuce and scallions interplant efficiently. Lettuce is shallow-rooted and quick while scallions send a narrow shank down with little leafy spread, so they occupy different space and the lettuce fills in between scallion rows. The scallion scent offers a little aphid deterrence over the lettuce as a bonus. Treat it as a space-and-timing pairing first, mild pest help second. Traditional
Brassicas (cabbage, broccoli)
Cabbage and broccoli like the same cool weather as scallions, and the strong scallion smell is thought to bother some of their pests.Scallions are a well-supported brassica companion. Their sulfur scent helps mask the cabbage family and deter its signature pests, cabbage loopers, worms, and root maggots, and extension trial work including scallion in a mix with broccoli showed reduced caterpillar damage. Alliums are shallow and undemanding, so they tuck between brassicas without competing for the heavy feeding those crops want. Research-backed
Provenance tagged inline · see methodology for the labeling system Key
Harvest signals

When to pick

Your scallions are ready when the green tops are about 6 to 8 inches tall and the white bottom is roughly as thick as a pencil. Do not wait for a round bulb to form, pull them while the base is still straight. Lift the whole plant, or with bunching types snip the tops about an inch above the soil and let them grow back. Smaller ones taste milder, bigger ones are a little stronger.Pull scallions once the green tops reach about 6 to 8 inches and the white shank is roughly pencil thick. There is no need to wait for a bulb: harvest at the straight-stem stage, before the base swells. Lift the whole plant, or cut bunching types about an inch above the crown and let them regrow. Younger is milder, so harvest on the small side for salads and a bit larger for cooking.

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Yield

What to expect

Each regular onion plant gives one scallion when pulled young, while bunching kinds grow back after you cut them, so you keep harvesting from the same clump.One scallion per plant for bulb-onion types pulled young; bunching types regrow after cutting for repeat harvests. A densely sown foot of row yields a generous handful.

If you sow a little at a time, you get scallions steadily for weeks instead of all at once, and bunching clumps keep producing.With succession sowing the harvest is continuous through the cool season rather than a single flush; bunching clumps deliver over many weeks. The two things that matter most for good scallions are thinning them to about an inch apart and keeping the soil evenly moist.Thinning to about an inch and keeping steady moisture are the biggest levers on tender, pencil-thick shanks in the first crop.

What changes yield
thinning to about an inchsteady moisturesuccession sowingharvesting before over-maturitycool-season timing
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Pick your variety

Recommended varieties

There are two kinds. Bunching onions like Evergreen Hardy White or Tokyo Long White never make a bulb, grow back after cutting, and many survive winter, so they are great for a patch you keep cutting. Regular onions like White Lisbon, sown close together and pulled young, give a fast scallion but you pull the whole plant once. Either works for the kitchen.Choose between two habits. True bunching types (Allium fistulosum) such as Evergreen Hardy White, Tokyo Long White, Beltsville Bunching, and Parade never form a bulb and many are perennial and very cold hardy, ideal for cut-and-come-again clumps. Regular bulb onions sown thickly and pulled young, such as White Lisbon, give a quick straight scallion but are pulled once, not divided. Clemson names Beltsville Bunching and Evergreen Bunching among types bred specifically for green-onion use.

Evergreen Hardy White
very cold-hardy bunching
White Lisbon
fast spring scallion
Tokyo Long White
long-shank bunching
Beltsville Bunching
heat and drought tolerant
Parade
uniform non-bulbing
Off the vine

Storing your harvest

Room temp
Scallions do not keep on the counter, they go limp within a day. Pick them close to when you will use them, or put them in the fridge right away.Scallions are not a room-temperature storage crop; they wilt within a day or two on the counter. Harvest close to use, or refrigerate promptly.
Fridge
Keep scallions in a plastic bag in the fridge, or stand them in a glass with a little water. They last about one to two weeks.Stand trimmed scallions in a little water or wrap them in a damp towel in a plastic bag in the crisper; they hold about one to two weeks (Clemson).
Freezer
You can chop scallions and freeze them for cooking. They go soft after thawing, so use them in cooked food, not raw in salads.Scallions freeze well chopped; texture softens, so use frozen scallion in cooked dishes rather than raw.
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From the garden to the kitchen

Recipes to try

BBQ & Grill

Grilled Chicken with Fresh Garden Salsa

BBQ & Grill · 40m · Serves 4
BBQ & Grill

Bell Pepper & Steak Skewers

BBQ & Grill · 32m · Serves 4
Salads

Radish Microgreen & Avocado Bowl

Salads · 10m · Serves 2
More recipes
arriving with the harvest
When something goes wrong

Common problems

01 of 03
02 of 03
03 of 03
The usual suspects

Pests & diseases

Pests
Onion thrips
P · 01
Cause A tiny insect called onion thrips. It multiplies fast in warm, dry weather and hides in the tight folds of the leaves.Onion thrips (Thrips tabaci) build through warm, dry spells, sheltering in the leaf axils where sprays miss them.
The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

  1. Garden sanitation

    When a sowing is finished, pull the leftovers and any onion volunteers instead of letting them stand, and clear the trimmings away from the bed. Thrips spend the winter in onion material left on the ground, so a bed cleared in fall gives them nothing to start from in spring.Onion thrips overwinter in allium material left on the soil surface and in volunteer plants, so clearing each finished sowing, its trimmings and any volunteers is the cultural control with the most support behind it. With scallions the whole plant is sold, so keeping the carryover population small matters more here than on a bulb crop.

  2. Water spray

    While the numbers are still light, a hard jet of water from the hose knocks thrips off. Aim into the crease where the leaves meet, since that is where they shelter. Spray early in the day so the leaves dry off, and keep the plants healthy and watered so they can carry the feeding they do get. If an infestation keeps building past this, your local extension office can tell you what is recommended in your area.A forceful water knock-down is the response to a light infestation, worked into the leaf axils where the insects sit. Those same folds are why coverage-dependent materials tend to underperform here, so vigor and steady water matter alongside the physical pass. Keep the pass to early in the day so foliage is not left wet, and take a persistent outbreak to local extension guidance rather than to a material named here.

No spray for this one. Prevention is the control.

Onion maggot
P · 02
Cause The larvae (maggots) of a small fly that lays its eggs at the base of the plants. It spends the winter in the soil where onions grew the year before, and old bulbs and rotting garden waste draw it in.Larvae of the onion maggot fly (Delia antiqua), which lays at the base of the plant; the pupae overwinter in the soil around last season's alliums, and cull piles and volunteer onions keep the fly going between crops. Rotting organic matter draws egg-laying, and cool, wet springs favor the maggots.
The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

  1. Crop rotation

    Do not put alliums back into the same bed year after year. The fly spends the winter in the soil where onions grew, so moving the planting keeps a new crop away from where it will come up in spring.The pupae overwinter in the soil around last season's alliums, so shifting the planting off that ground, and away from any cull pile, is the foundation the rest of the program sits on.

  2. Garden sanitation

    Clear out old onion plants, roots and all, plus any small or damaged bulbs you did not use, once a bed is finished, and take them away rather than leaving them lying around. Old onion material is what the fly breeds in, and pulling the plants with their roots takes the pupae out with them.Culls, volunteer onions and plants left standing are what the fly breeds in and overwinters around, so pull the finished crop with its roots, clear culls and volunteers, and take them out of the garden rather than leaving them in place. Keep fresh manure and green manure out of the bed in spring, since rotting organic matter draws the flies to lay.

  3. Floating row cover

    Lay a floating row cover, a light fabric that lets in light and water while keeping insects out, over the bed as soon as you sow, so it is in place before the flies are out. The fly has to reach the base of a plant to lay its eggs, so a sealed cover shuts that out. Do not use a cover on a bed where alliums grew last year, or you can seal the emerging flies in with the crop.Cover from sowing, before the spring flight is laying, and seal the edges: eggs go in at the plant base, so the barrier counts only if the fly cannot get underneath it. It belongs on rotated ground, since covering a bed that carried alliums last season traps the flies emerging from the soil under the net with the crop.

No spray for this one. Prevention is the control.

Allium leafminer
P · 03
Cause A small fly whose grubs tunnel inside allium leaves. It is active in spring and fall.The allium leafminer (Phytomyza gymnostoma), active in spring and fall, lays eggs in the leaves; larvae mine down toward the base.
The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

  1. Crop rotation

    Grow your alliums somewhere new each year rather than returning to the same bed. Rotating the planting is part of keeping this fly from settling into one patch of the garden.Rotate off last year's allium ground. With flights in both spring and fall working the same crop group, a planting left in place offers the same target twice a season.

  2. Garden sanitation

    Pull off and get rid of leaves showing the tunneling or the rows of small white dots, and clear infested material out of the bed rather than leaving it there.Strip and destroy mined foliage and infested debris. The larvae feed inside the leaf tissue and work down toward the base, so taking the tissue out takes them with it.

  3. Floating row cover

    Cover the plants with fine insect netting during the spring and fall stretches when the fly is out. It cannot lay eggs in leaves it cannot land on. Pair the netting with rotation so you are not covering ground that carried alliums the year before.Netting across both flight periods is the primary control here. Adults puncture and feed on the leaf and lay into it, so exclusion has to be up ahead of a flight rather than after the rows of white dots appear, and it belongs on rotated ground rather than over a repeat allium bed.

No spray for this one. Prevention is the control.

Diseases
Botrytis neck rot
D · 01
Cause A mold that gets into wet, crowded leaves. Watering over the top and too much fertilizer make it worse.Botrytis infection of wet, crowded foliage; overhead watering and excess nitrogen worsen it.
The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

  1. Airflow and spacing

    Give the plants room when you sow or set them out so air can move between them. Crowded scallions hold dampness around the leaf bases, and that is the setting this mold gets going in.Spacing is set once, at planting, for air movement through the stand. Crowding is one half of the condition this rot wants and foliage that stays wet is the other, so a stand that dries quickly takes pressure off both.

  2. Water at the base

    Put the water on the soil rather than over the leaves. Watering from above wets the tops and the leaf bases, and this rot starts where they stay wet.Deliver water to the root zone rather than across the canopy. Overhead irrigation is called out as a factor, and the neck and leaf bases are where the soft, sunken rot actually appears.

  3. Balanced nitrogen feeding

    Go easy on the fertilizer. Too much nitrogen, the nutrient that drives leafy growth, pushes out soft, thick growth that holds dampness longer.Excess nitrogen sits alongside overhead watering in the guidance as something that worsens this one. Heavy feeding thickens the stand and slows how fast it dries, so restrained feeding is preventive rather than corrective.

  4. Staying out of wet foliage

    Harvest when the leaves are dry rather than straight after rain or while the dew is still on the plants. Lingering wetness on the tops is the condition this rot favors, so pick your moment.This rung is about when you work rather than what you apply: take the crop on dry days, because leaf wetness that lingers is the condition tied to this rot, and dew and rain leave foliage wet regardless of how you irrigate.

No spray for this one. Prevention is the control.

Fusarium basal rot
D · 02
Cause A soil fungus that stays in the ground for years and likes warm soil. Injuries and insect damage let it in.Soilborne Fusarium that persists for years and is favored by warm soil; wounds and maggot damage open the door.
The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

  1. Crop rotation

    Keep alliums out of an affected bed for several years, not just one season. This fungus stays alive in the soil for a long stretch, so a single year away is not much of a gap.The pathogen is soilborne and persists for years, so the rotation is measured in several seasons away from alliums rather than the usual one-year shuffle. Warm soil favors it, which makes the rotation the lever with the longest reach here.

  2. Resistant varieties

    If you can find seed or plants described as resistant to this rot, start there. Not every scallion is offered that way, so treat it as a bonus when it is available.Take resistant stock where it is offered; availability is the limiting factor rather than the value of the trait, and it is one of the few levers that remains on ground already carrying the fungus.

No spray for this one. Prevention is the control.

White rot
D · 03
Cause A soil fungus whose tough resting bodies survive in the ground for many years. Cool, damp conditions make it worse.The soilborne fungus Sclerotium cepivorum, whose sclerotia survive in soil for many years; cool, moist conditions favor it.
The control ladder

The ladder troubleshoots from the gentlest solution to the strongest. Start with the gentlest option and only move on when and if it doesn't work.

  1. Clean planting stock

    Start with transplants you have reason to think are clean, since this fungus can arrive on the planting material itself. There is no known cure once it is in the soil, so the effort goes into keeping it out rather than treating it later.Clean planting stock is the decision that carries the most weight here because it is made before anything reaches the ground. No cure is known for infested soil, so introduction is the failure mode worth preventing.

  2. Crop rotation

    If a bed has had it, keep alliums well away from that spot for many years. The fungus leaves behind tough little resting bodies, the tiny black specks you find at the base of a sick plant, and they hold on in the ground a long time. Avoid moving soil out of that bed into clean ground.Sclerotia, the resting bodies, survive in soil for many years, so the rotation is a long one and it is measured in distance from the infested ground as much as in seasons. It also comes undone if the soil itself travels, so keep soil from an affected bed out of clean beds.

No spray for this one. Prevention is the control.

Verified · 6 sources View
Seasoned
Where to plant next year

Crop rotation

Scallions do well planted after leafy greens or beans and peas. Just do not plant beans or peas right next to scallions, since onions can slow those down.Scallions follow well after a leafy or legume crop and pair poorly before beans and peas, which alliums tend to inhibit.

Family
Allium
Years between
3 years
in the same bed
Avoid following
Do not plant scallions where you grew onions, garlic, or leeks recently. Some allium diseases live in the soil and build up. Wait at least 3 years before growing alliums in the same spot again.Avoid following onions or other alliums (garlic, leeks, shallots) in the same ground; allium diseases such as pink root and white rot persist in soil. A home garden can target at least 3 years between allium crops.
Plant after
leafy greens or legumes
Verified · 2 sources View
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 spring onion / scallion season. The wording adjusts to whichever you pick: beginner or seasoned. Here are three you'll see in Zone 9.

p
plant
2 weeks before last frost
Time to plant scallions Sow scallions
Plant scallion seeds outside as soon as you can work the soil. They handle cold, so you do not need to wait for warm weather. Plant shallow and thin them later to about an inch apart. Direct-sow scallion seed as soon as the soil is workable; the crop is cold hardy and does not wait for warm weather. Sow shallowly and plan to thin to about an inch.
p
plant
2 weeks after last sowing
Plant more scallions Sow the next scallion succession
Plant another short row of scallions now, a couple of weeks after the last one, so you always have some coming along. Sow another short row now, about two to three weeks after the last, so scallions keep coming in sequence through the cool season rather than all at once.
p
plant
8 weeks after sowing
Check your scallions Scallions should be sizing up
About 50 to 70 days after planting, start picking scallions when the tops are 6 to 8 inches tall. Pull the biggest ones first to give the others room. Around 50 to 70 days from sowing, start pulling scallions once the tops reach 6 to 8 inches. Harvesting the largest first gives the rest room to size up.
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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.

Research-backed Documented in cooperative extension publications or peer-reviewed research
Well-grounded A known agronomic principle, but not formally tested for this specific pair
Traditional Time-tested gardening wisdom, limited formal research support
Last reviewed
June 30, 2026
Data version
crops_data_final · v1.0 · schema 2.9
Sources cited on this page
16 publications
Verified entries
Companion-planting claims tagged inline · zone dates verified against 5+ extensions
See all sources cited on this page
  • University of Minnesota Extension umn_ext
  • University of Maryland Extension umd_ext
  • Cornell Cooperative Extension cornell_ext
  • Iowa State University Extension iastate_ext
  • Michigan State University Extension msu_ext
  • NC State Extension ncsu_ext
  • Penn State Extension psu_ext
  • U. of Illinois Urbana-Champaign Extension uiuc_ext
  • UC Davis Postharvest Center ucd_postharvest
  • Texas A&M AgriLife Extension tamu_agrilife
  • Virginia Cooperative Extension 426-331 vce_426_331
  • Piedmont Master Gardeners piedmont_mg
  • UGA Vegetable Garden Calendar uga_calendar
  • Clemson Home & Garden Information Center clemson_hgic
  • UC IPM Statewide IPM Program uc_ipm
  • NOAA 1991-2020 Climate Normals noaa_normals

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Vol. 003 · Spring Onion / Scallion · plant.lifestyle