How to Grow Tatsoi

Tatsoi Plant

Marie Iannotti

Asian greens may look exotic, but most are easy to grow in your own vegetable garden. Tatsoi (pronounced taht-SOY) is a non-heading mustard that is very similar in flavor to bok choi. Tatsoi plants tend to grow in a flatter rosette than bok choi, with long, spoon-shaped leaves. You may find them sold loose leaf or bunched together like celery. If you'd like to try your hand at growing tatsoi, you'll be pleased to learn how undemanding it is. As with most Asian greens, it grows quickly and with few problems.

Tatsoi leaves grow in a low, somewhat flattened rosette. The crisp stalks are a pale green and the spoon-shaped leaves are much darker. Tatsoi flowers have the familiar four-petal cross of plants in the cruciferous family. These greens can be planted in spring (for an early summer harvest) or late summer (for a fall harvest). They grow quickly and can be ready for harvest in as few as 20 days.

Botanical Name  Brassica rapa subsp . narinosa 
Common Name  Tatsoi, Tah Tsai, Spoon mustard, Spinach mustard, Rosette bok choy
Plant Type  Biennial  
Mature Size  8-10 in. tall, 12 in. wide 
Sun Exposure  Partial sun to full sun
Soil Type  Rich, well-drained
Soil pH  Neutral (6.5 to 7.0)
Bloom Time  Seasonal
Flower Color  Yellow 
Hardiness Zones  4 to 7 (USDA)
Native Area  Asia 
Toxicity  Non-toxic 

Tatsoi Care

You can succession plant tatsoi every two to three weeks for a longer harvest period. Stop planting when the weather turns hot, then start new plants for the fall in late summer.

Plants in the brassica family do not cross-pollinate with plants outside their species. Seed can be saved for up to four years.

Fall-grown tatsoi usually does better than seed sown in the spring. Besides the greater chance of the seedlings experiencing cold temperatures or frost in the spring causing them to bolt, there are also fewer insect pests in the fall.

Tatsoi has the odd habit of growing flat in cold weather, but more upright in heat.

Light

Tatsoi grows best in partial sun, about three to five hours each day is ideal but it can handle full sun if it is kept well watered.

Soil

Provide a well-draining soil with a lot of compost or other organic matter mixed in. Tatsoi grows in soil with a pH from 6.0–7.5, with 6.5–7.0 the ideal range.

Water

As with most leafy vegetables, tatsoi needs regular watering or it will bolt to seed.

Temperature and Humidity

Tatsoi plants are biennial and may survive undercover in USDA hardiness zones 4 through 7; however, they will quickly bolt to seed in the spring. These greens grow best in temperatures from 60 to 70 degrees Fahrenheit and may bolt if the temperature drops to 50 degrees Fahrenheit.

Fertilizer

If your soil is rich, you should not need to feed the plants. Otherwise, use a fertilizer high in nitrogen.

Tatsoi Varieties

Although there are named varieties of tatsoi, you will probably find only seed packets in stores that are labeled simply "Tatsoi," and those can have either white or green stalks. There is a nice savoyed variety that grows a little larger and more upright. Specialty seed catalogs may offer the following:

  • 'Black Summer': Plant in fall and harvest into winter; very dark leaves
  • 'Ching-Chiang': A quick-growing dwarf variety that can handle early spring weather
  • 'Joi Choi': A medium-sized plant with good bolt-resistance
  • 'Mei Qing Choi': Dwarf variety with a fast growth rate and tight green heads
  • 'Win-Win': Extra large, dense heads; slow to bolt

Harvesting

You can start harvesting tatsoi leaves when they are about 4 inches long. Dwarf tatsoi matures in 20 to 25 days; full-size tatsoi takes 40 to 50 days. To harvest the whole head, slice the plants off about 1 inch above the ground, and they should re-sprout for you. The new plants will be smaller but still delicious.

Tatsoi has slightly more of a tangy mustard flavor than bok choy. It is often found in salad mixes and can be cooked in any dish where you would use bok choy, such as stir-fries, soups, and side dishes. The mild and tender baby leaves taste very similar to spinach and are a good substitute when it is too warm to grow spinach plants.

How to Grow Tatsoi From Seed

You can direct sow or start seed indoors about four to five weeks before your last frost date. Begin sowing outdoors after your last frost date. Don't rush it; young plants will bolt if they experience too much cold weather. Seeds are quick to germinate, usually within four to eight days.

Plant seed 1/4 to 1/2 inch deep, spaced 1 inch apart. Thin and eat the plants when they are a couple of inches tall. If you are growing full-sized plants, thin to a spacing of 6 to 8 inches.

Common Pests

Tatsoi is generally disease-free, but insects love its tender leaves. Cabbage worms, cabbage loopers, and flea beetles can riddle the leaves in spring unless the plants are protected with row covers. The ground-hugging leaves are extremely attractive to slugs. Whiteflies and aphids are less of a problem.