Green Tatsoi
Gardyn
YoungTatsoi seedlings at the 4-6 leaf stage in plug trays, ready to transplant (Forest & Kim Starr, Olinda, Maui; CC BY 3.0 US).
Species-level tatsoi (Brassica rapa var. narinosa/rosularis); unnamed green strain.
Photo: Forest and Kim Starr· CC BY 3.0 us
GrowingHalf-grown tatsoi in a winter garden bed, rosette beginning to flatten and fill in but leaves still upright and light green (Kanagawa, Japan, Jan 2026; CC BY 4.0).
Species-level green tatsoi.
Photo: Nesnad· CC BY 4.0
Full grownHarvest-size tatsoi: a dense, flat, dinner-plate rosette of glossy dark spoon-shaped leaves in a garden bed (Obelix Village kebun sayur; CC BY 3.0).
Species-level green tatsoi.
Photo: Indonesiagood· CC BY 3.0
Growing stages
What to look for, and what to do, at each point in its lifeGreen Tatsoi is one of the most cold-hardy greens for Decatur's Zone 8a, sown in September for a winter-long harvest under light cover and again in February-March before spring heat pushes it to bolt.
- 1
Sowing
Early-mid September (fall crop) or mid-February to early March (spring crop)You'll see Seeds are tiny, round, and dark reddish-brown, showing nothing above ground for 4-7 days.
Do Direct sow 1/4 inch deep and keep the soil surface consistently moist until sprouting.
- 2
Seedling
Days 4-16 after sowingYou'll see Round seed leaves appear first, then dark green, glossy, spoon-shaped true leaves that begin forming a tight, flat rosette low to the ground.
Do Thin to 6-8 inches apart, and watch for flea beetle shot-holes.
- 3
Cut-and-come-again or whole-plant harvest
Starting 25-30 days after sowing for baby leaves, 40-45 days for a full flat rosetteYou'll see The rosette spreads flat and wide, 8-12 inches across, with glossy dark green spoon-shaped leaves radiating from a central crown.
Do Harvest outer leaves as needed, or cut the whole rosette at the base.
- 4
Bolting
Late spring, typically April-May, once daylength lengthens and temperatures push past 70-75°FYou'll see A central stalk shoots up from the flat rosette, leaves turn narrow, and small yellow four-petaled flowers cluster at the top.
Do Harvest what remains before leaves turn bitter, then pull the plant or let one flower for pollinators and seed.
- 5
Seed saving
4-8 weeks after bolting, once seed pods dry from green to brownYou'll see Flower stalks turn from yellow blooms to slim, brown, brittle pods that rattle with seed when dry.
Do Cut dry seed stalks into a paper bag, finish drying, then crush and winnow to collect seed.
Techniques — transplant, prune, propagate, divide, seed
Full sun to part shade; cool weather.
Consistent moisture.
Hydro pods / tight in-ground spacing.
Steady light feeding.
Care
- Cool-season crops — spring and fall windows; they bolt in summer heat.
- Wasabina mustard + tatsoi run permanently indoors in the 2nd hydro unit.
- Giant Red + Southern Green mustard run outdoors in the wooden structure.
Harvest
Cut-and-come-again; harvest outer leaves.
Watch for
Bolting in heat; aphids/flea beetles.