How do you grow tatsoi microgreens? Sow about 7.5 grams of tatsoi seed on a moist 10×20 tray, press it in, and keep it covered near 75°F (24°C) until it germinates. Then uncover under light, bottom water, and cut when the first true leaves appear. Johnny’s Selected Seeds reports an average of 13.5 days to harvest.
Key takeaway: Tatsoi microgreens give you dark green, spoon-shaped leaves with a mild, bok choy-like flavor in about two weeks. Johnny’s Selected Seeds lists tatsoi (Brassica rapa var. narinosa) in its fast-growing 10–15 day microgreen group, and NC State Extension describes young tatsoi leaves as crisp, thick and tender with a mild taste.
| Factor | Guideline | Source |
|---|---|---|
| Seeding rate for tatsoi microgreens | 7.5 g per 1020 tray (about 3.5 flats per oz) | Johnny’s Selected Seeds |
| Days to harvest | About 13.5 days to first true leaf | Johnny’s Selected Seeds |
| Germination temperature | 75°F (24°C), then 60°F (16°C) root zone | Johnny’s Selected Seeds |
| Air temperature | 65–75°F (18–24°C) | Johnny’s Selected Seeds |
| Harvest height | 1/2–2 in (1–5 cm) | Johnny’s Selected Seeds |
| Storage caution | Very sensitive to ethylene; leaves yellow | SARE |
What Do Tatsoi Microgreens Taste Like?
Mild and fresh, like baby bok choy. NC State Extension says tatsoi’s flavor is similar to bok choy and that its young leaves are crisp, thick and tender with a mild taste. Johnny’s describes the microgreens as dark green with spoon-shaped leaves and a mild flavor, which makes tatsoi a good base for spicier mixes.
- Look: dark green, rounded, spoon-shaped leaves.
- Taste: mild, sweet and green.
- Pair with: radish, mustard or mizuna micros.
How Much Seed Do Tatsoi Microgreens Need?
About 7.5 grams per tray. Based on its yield trial, in which each 1020 flat was weighed before and after seeding, Johnny’s recommends 7.5 g of tatsoi seed per tray, or roughly 3.5 flats per ounce. It lists about 215,100 seeds per pound. Penn State Extension suggests up to about 12 seeds per square inch (6 per cm²) for small-seeded brassicas.
Use our microgreen seed density guide to adjust for smaller trays.
How Do You Grow Tatsoi Microgreens Step by Step?
Use the standard brassica method. Johnny’s says to broadcast seed thickly on potting mix or a soilless medium in shallow trays, 1/8–1/4 inch (3–6 mm) apart, press seeds firmly into the surface, and cover lightly with mix, vermiculite or a humidity dome. Seeds can germinate on heat mats, in germination chambers or on benches.
- Fill a 1020 tray with moist mix or a hydroponic grow mat.
- Weigh out about 7.5 g of untreated tatsoi seed.
- Scatter evenly and press seed into the surface.
- Cover with a light layer of mix or a blackout lid.
- Hold the root zone near 75°F (24°C) to germinate.
- Uncover once sprouted and place under light.
- Bottom water to keep the medium evenly moist.
What Temperature and Light Do Tatsoi Microgreens Need?
Cool after germination. Johnny’s recommends 75°F (24°C) soil until germination, then 60°F (16°C), with air at 65–75°F (18–24°C), warning that temperatures above 75°F (24°C) increase disease and inhibit germination. NC State Extension notes tatsoi is a cool-weather crop, and SARE says it does poorly in hot, dry weather. Oregon State University Extension suggests about 15 hours of lamp light a day.
- Blackout: about 3–4 days, until sprouts appear.
- Light: a lamp about 3 inches (7.5 cm) above the greens.
- Heat: avoid warm, still air.
How Do You Water Tatsoi Microgreens?
Bottom water. Johnny’s recommends bottom watering or misting so the mix does not splash onto the leaves, and says never to let the medium dry out. Plain water is usually enough in potting mix; on nutrient-free hydroponic mats, Johnny’s says a dilute fertilizer solution is appropriate, applied by bottom watering to avoid leaf residue. Shallow microgreen trays with a solid under-tray make this easy.
When Do You Harvest Tatsoi Microgreens?
At about 13.5 days. Johnny’s trial averaged 13.5 days to maturity when tatsoi was cut at the first true leaf stage instead of the cotyledon stage. Harvest at 1/2–2 inches (1–5 cm) tall with clean scissors or a sharp knife, just above the medium, and minimize handling. Penn State Extension says microgreens are generally harvested 7 to 21 days after germination.
How Do You Store Tatsoi Microgreens?
Cold, dry and away from ethylene. Johnny’s says microgreen shelf life is 5 to 10 days under proper storage and that they must be washed before serving. SARE warns that tatsoi is highly sensitive to ethylene exposure, which turns the leaves yellow, so allow good air exchange and do not store it with crops that release ethylene. Oregon State University Extension suggests wrapping greens in a paper towel inside a bag.
Why Are My Tatsoi Microgreens Yellow or Moldy?
Check light, airflow and moisture. Yellow, stretched seedlings usually mean too little light after the blackout period; Oregon State University Extension notes dim light causes leaning, leggy growth. Johnny’s says dense plantings are prone to damping-off in saturated media with poor air circulation, and recommends fans, clean media and water, and correct seeding density. Our microgreens mold guide covers the fixes.
Is Tatsoi the Same as Bok Choy?
They are close relatives. SARE classifies tatsoi as Brassica rapa in the narinosa group, and NC State Extension lists it as rosette pak choi with a flavor similar to bok choy. Both make mild microgreens, so you can grow them side by side; our bok choy microgreens guide covers the other.
FAQ About Tatsoi Microgreens
How long do tatsoi microgreens take to grow?
About 13.5 days to first true leaf, per Johnny’s trial.
How much seed do I need per tray?
About 7.5 g per 1020 tray.
What do tatsoi microgreens taste like?
Mild, similar to bok choy.
Can tatsoi microgreens be grown hydroponically?
Yes, on grow mats with bottom watering.
Why do my tatsoi microgreens turn yellow in the fridge?
Ethylene exposure can yellow tatsoi leaves.
How tall should they be at harvest?
About 1/2–2 inches (1–5 cm).
Sources
- Johnny’s Selected Seeds — Tatsoi Organic Microgreen Seed
- NC State Extension — Brassica rapa var. rosularis (Tat Soi)
- SARE — Northeast Crop Production and Harvest Manual: Tatsoi
- Penn State Extension — The ABCs of Microgreens
- Oregon State University Extension — Microgreens
- Johnny’s Selected Seeds — Microgreens Seeding Density and Yield Trials
- Photo credits (Wikimedia Commons, edited with titles): Tatsoi by baldeaglebluff (CC BY-SA 2.0); Brassica rapa subsp narinosa by Idéalités (CC BY-SA 4.0); Tatsoi – January 2026 – Sarah Stierch by Missvain (CC0)