The GuideMicrogreens Vol. 012

Microgreens mix

grown indoors, any week of the year

Broccoli microgreens are baby broccoli plants that you harvest very young, about 8 to 12 days after planting, when they are just a couple of inches tall. You grow them indoors all year on a shallow tray of seed-starting mix or a special growing mat. The steps are always the same: scatter the small seeds thickly and dry (no soaking needed), cover the tray to keep it dark for about 3 to 4 days while they sprout, then move it into the light to green up, then snip and eat. The taste is mild, fresh, and a little cabbage-like. Broccoli is one of the most popular microgreens because it is so nutritious, packed with the healthy plant compounds the cabbage family is known for, and young microgreens tend to be richer in vitamins than full-grown plants. There is no outdoor season or weather to worry about, so they grow the same way no matter where you live.Broccoli microgreens are the young seedlings of broccoli (Brassica oleracea var. italica), harvested at the cotyledon to first-true-leaf stage about 8 to 12 days after sowing. They are grown indoors year-round in a short repeatable cycle: a dense, dry, even sow on a shallow tray of mix or a fiber mat (broccoli needs no presoak), a brief dark blackout of about 3 to 4 days to drive even germination and stem stretch, then light to green up, then a single cut. The flavor is mild, fresh, and faintly cabbage-like. Broccoli is one of the most popular microgreens for nutrition; like other brassica microgreens it concentrates the glucosinolates that give the cabbage family its character, and research finds microgreens generally higher in vitamins and phytochemicals than the mature vegetable. Because there is no frost, season, or hardiness zone involved, the same tray grows identically on a windowsill anywhere.

Broccoli Microgreens, ready to cut
Fig. 01 · Broccoli MicrogreensIndoor
Ready in
8-12
days, sow to harvest
Difficulty
Easy
beginner crop
Grows
Indoors
year round, any season
Resow
Weekly
for a steady supply
The cycle, start to finish

Sow, dark, light, harvest, then again

Indoors, every week of the year. Most mixes are ready in 8 to 12 days; start a fresh tray every week for a steady supply.

  1. Step 01 Day 0

    Sow

    An even, crowded scatter of seed covering the whole surface, over mix that looks uniformly damp and dark but has no standing water.A uniform, dense seed layer with no clumping on evenly moist medium.

    From plant Dampen the growing medium so it feels like a wrung-out sponge, then scatter broccoli seeds thickly and evenly (about 1 ounce per standard tray). Do not soak them first. Press the seeds down so they touch the surface, but do not cover them with soil.Pre-moisten the medium to wrung-sponge feel, then broadcast broccoli seed densely and evenly, about 28 grams (1 ounce) per 1020 tray. No presoak; broccoli goes on dry. Press seed into contact but do not bury it; buried seed greens poorly and traps moisture against the stems.
  2. Step 02 Covered · ~74°F

    Germination

    Seeds swelling and splitting, with tiny white roots and pale looped stems appearing quickly, often lifting the cover within a day or two.Rapid imbibition and splitting; white radicles and blanched hypocotyls emerging early, lifting the cover.

    From plant Put the cover on and keep the tray warm (around 74 °F) and dark. Mist lightly so the surface stays damp but not wet. A small weight on the cover helps the roots push down. Broccoli sprouts quickly.Cover the tray and keep it warm (about 74 °F) and dark. Mist to hold even surface moisture, never soggy. A light weight on the cover keeps seed in firm contact so roots drive down rather than lifting the seed. Broccoli germinates fast, often within a day or two.
  3. Step 03 1 to 4 days · dark

    Blackout

    A dense mat of pale, stretched stems standing tall and lifting the cover. They will be white to yellow, not green yet, which is exactly right in the dark.Uniformly elongated, blanched stems lifting the cover; a tall, even pre-greening stand.

    From plant Keep the covered tray in the dark for about 3 to 4 days. The darkness makes the stems grow taller and more even before you give them light. If you see fuzzy white on the roots, do not panic; it is usually normal root hairs, not mold.Hold the weighted cover in the dark for about 3 to 4 days (roughly 2 to 4 by conditions), then take the cover off the canopy. The dark stretch lengthens and evens the stems before greening. Soon after germination you may see fine white fuzz on the roots; this is usually normal root hairs, not mold.
  4. Step 04 18 h light · 68 to 72°F

    Light

    Stems and seed leaves turning from pale to bright green within a day, standing up straight. A small first true leaf may appear at the center of some.Rapid greening of cotyledons; first true leaf may form.

    From plant Uncover the tray into bright light for about 16 to 18 hours a day at 68 to 72 °F, and start watering from the bottom so the leaves stay dry. Keep a gentle fan going to prevent mold. Cut when the first little leaves are open.Uncover into 16 to 18 hours of bright light at 68 to 72 °F and switch from misting to bottom-watering so foliage stays dry. Run a gentle fan; broccoli's dense canopy plus high humidity is the damping-off window. Harvest at cotyledon to first true leaf.
  5. Step 05 Day 8 to 12

    Harvest

    Open, fully green seed leaves standing about one to two inches tall, sometimes with a tiny true leaf showing. The flavor is fresh and mild.Cotyledons fully expanded and green at 1-2 in, first true leaf just emerging; mild flavor.

Then start again. Sow a fresh tray every week, and there is always a crop a few days out.
The specs

Care guide

The numbers that matter, at a glance.

Sunlight
bright indirect light or a grow light
Water
keep the medium evenly moist; bottom-water once greened to keep leaves dry
Days to maturity
8-12 days
Container OK?
Yes
Germination temp
70-75°F
Soil chemistry

Soil pH for broccoli microgreens

You do not need to worry about soil pH for broccoli microgreens. The mixes and mats sold for microgreens are already fine as is.pH is not a practical lever for a single short indoor cycle on a soilless medium; standard seed-starting mixes and coir sit in a workable range and need no adjustment for broccoli.

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Steady hand on the hose

Watering

When & how much
Frequency
While the seeds are sprouting, lightly mist the surface once or twice a day so it stays damp. After you move the tray into the light, water from the bottom whenever it starts to dry out.Mist once or twice daily through germination and blackout to hold even surface moisture; once greened, bottom-water as the tray dries.
Amount
Just enough to keep the medium damp like a wrung-out sponge, never soggy. After bottom-watering, tip out any water left sitting in the tray.Enough to keep the medium at wrung-sponge moisture, never saturated; pour off any standing water after bottom-watering.
Method
Mist the top while the seeds are sprouting, then water from the bottom once the leaves are up so the leaves stay dry.Mist during germination and blackout; switch to bottom-watering (sub-irrigation) once the canopy is up so broccoli's dense foliage stays dry.
Signs of trouble
Too much water
Water sitting in the tray, a bad smell, fuzzy white mold on the mix and stems, or seedlings flopping over mean it is too wet. Cut back on water and improve airflow.Standing water, a sour or musty smell, fuzzy white growth spreading over the medium and stems, and seedlings collapsing at the base all signal overwatering and the damping-off that follows it.
Too little water
Limp, curling leaves and mix that has shrunk away from the sides mean it got too dry. Water from the bottom right away.Curling, limp cotyledons and a medium that has pulled away from the tray edges indicate the canopy has dried too far between waterings.
Feeding rhythm

Feeding

Frequency
none
Type
none needed
When to start
not applicable

You do not need to feed broccoli microgreens. The seed carries enough food to reach harvest in a week or two, and adding fertilizer just invites algae and odd flavors. Plain water is all they need.Broccoli microgreens are cut in about 8 to 12 days, well before they exhaust the seed's own reserves, so no fertilizer is needed for a single cycle on an inert medium or seed-starting mix. Little or no feeding is the norm; clear water grows a good tray, and added nutrients mainly raise the risk of algae and off-flavors.

Harvest signals

When to pick

Your broccoli microgreens are ready when the first little seed-leaves are open and, for many, the first true leaf is just showing, usually about 8 to 12 days after sowing and a couple of inches tall. Snip them just above the medium with clean scissors and eat them fresh. They do not grow back, so you start a new tray each time.Cut at the cotyledon to first-true-leaf stage, typically 8 to 12 days from sowing, when the stand is about 2 to 3 inches tall. Snip just above the medium with clean scissors; broccoli will not regrow, so the tray is a single cut.

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Yield

What to expect

You measure broccoli microgreens by the tray, not by each plant. A full tray usually gives you a few good handfuls (roughly 8 to 12 ounces).Yield is measured per tray, not per plant: a well-sown 1020 tray of broccoli returns roughly 8 to 12 ounces of cut microgreens depending on seeding rate and conditions.

Each tray gives one harvest at its best. To keep a steady supply, start new trays every few days.Every tray is a single harvest at peak; continuous supply comes from staggered sowings, not from regrowth. There is no waiting period with microgreens. Your very first tray works just like the rest; you will get a feel for how much to sow and water after a few tries.There is no establishment year; the first tray performs the same as any later tray. Expect to dial in seeding rate and watering over the first few cycles.

What changes yield
seeding density (too sparse wastes the tray; too dense traps moisture and invites damping-off)even moisture and the mist-to-bottom-water transitionconstant gentle airflowseed freshness and microgreen-grade qualitylight intensity and the full 16 to 18 hour daily duration
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Pick your variety

Recommended varieties

Standard broccoli is the go-to: a mild, fresh microgreen from small seeds you scatter dry (no soaking), ready in about 8 to 12 days. It is one of the most popular microgreens for nutrition, since broccoli and its relatives are packed with the healthy plant compounds the cabbage family is known for, and young microgreens tend to be richer in vitamins than full-grown plants. If you want more kick, broccoli raab (rapini) is a spicier, peppery option, though it is actually a close cousin (in the turnip family), not true broccoli. Never grow microgreens from tomato, pepper, or eggplant seed, as those baby plants are not safe to eat.For a mild, versatile tray, standard broccoli (Brassica oleracea var. italica) is the mainstay: small brassica seed sown densely and dry (no presoak), finishing in about 8 to 12 days. Broccoli is one of the microgreens most often grown for nutrition; like other brassica microgreens it concentrates the glucosinolates that give the cabbage family its character, and research finds microgreens generally higher in vitamins and phytochemicals than the mature vegetable. For a sharper tray, broccoli raab (rapini) is a peppery alternative, but note it is a different species (Brassica rapa, closer to turnip) rather than true broccoli. Never grow microgreens from solanaceous seed (tomato, pepper, eggplant); those seedlings are not safe to eat raw.

Standard broccoli (e.g. Calabrese, Waltham 29, Di Cicco)
Brassica oleracea var. italica; mild, fresh, faintly cabbage-like. About 8 to 12 days, no presoak. The usual choice and the one prized for its glucosinolate content.
Broccoli raab / rapini
A spicier, peppery alternative; botanically Brassica rapa (turnip family), not true broccoli. Finishes fast (about 6 to 10 days), no presoak. Use for a sharper, more mustard-like tray.
Off the vine

Storing your harvest

Room temp
Do not leave cut broccoli microgreens out on the counter. They go limp fast, so put them in the fridge right after cutting.Do not hold cut broccoli microgreens at room temperature; they wilt within hours. Refrigerate immediately after cutting.
Fridge
Rinse cut broccoli microgreens, pat them dry, and keep them in the fridge in a container with a paper towel to soak up extra moisture. They are delicate, so use them within about a week (up to 10 days if kept dry).Rinse, pat dry, and refrigerate in a vented container lined with a paper towel; broccoli is a tender brassica and keeps best used within about 5 to 7 days, up to about 10 with careful drying. Harvest only what you will use soon.
Freezer
Do not freeze broccoli microgreens. Freezing turns them mushy. They are meant to be eaten fresh.Not recommended. Freezing collapses the delicate cells and ruins the texture. Broccoli microgreens are a fresh, cut-and-eat crop.
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The usual suspects

Pests & diseases

Pests
Fungus gnats
P · 01
What it is Tiny dark flies that show up around constantly damp medium. Their larvae live in the wet mix. They usually just mean the tray is staying too wet.Small dark flies whose larvae live in persistently wet medium and feed on organic matter and tender roots. On a broccoli tray they are a symptom of an over-wet medium rather than a primary threat, and the short cycle usually beats them.
Diseases
Damping-off and moldDamping-off (and surface mold)
D · 01
What it is The most common broccoli microgreen problem. In wet, crowded, stuffy conditions, tiny fungi rot the baby plants right at the base, and you often see fuzzy white mold on the surface and stems too. Broccoli is packed in tightly, so it is especially prone to this.Soil-borne fungi and water molds (Pythium, Rhizoctonia, and Fusarium) rot seedlings at the base under wet, crowded, still conditions, often alongside fuzzy white cobweb-like growth on the medium and stems. Broccoli is a small, densely sown brassica and is notably prone to it; on Penn State's trials damping-off was the only disease or pest issue encountered.
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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
July 2, 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. 012 · Broccoli Microgreens · plant.lifestyle