Overview and Description

Tatsoi (pronounced taht-SOY), a non-heading mustard, is very similar to bok choi. It tends to be a flatter rosette with long, spoon-shaped leaves. You may find it sold loose leaf or bunched together like celery. As with most of the Asian greens, it grows quickly, with few problems.

• Leaves: Leaves grow in a low, somewhat flattened rosette. The crisp stalks are a pale green and the spoon-shaped leaves are much darker.

• Flowers: Tatsoi flowers have the familiar 4-petal cross of plants in the cruciferous family.

Botanical Name

Brassica rapa subsp. narinosa

Common Name:

Tatsoi, Tah Tsai, Spoon mustard, Spinach mustard, Rosette bok choy,

Hardiness Zone

The plants are biennial. It may survive under cover in USDA Hardiness Zones 4 - 7. However it will quickly blot to seed, in the spring.

Sun Exposure

Tatsoi does best in partial sun, about 3 - 5 hours each day but can handle full sun, if it is kept well watered.

Mature Size

Full size heads will grow to about 8 - 10 inches. Spread depends on whether the leaves are flattened or upright, but figure about 12 inches per plant.

Days to Harvest

You can start harvest leaves when they are about 4 inches. Baby tatsoi matures in 20 - 25 days. Full size tatsoi takes 40 - 50 days.
Slice the plants off about an inch above the ground and they should re-sprout for you. The plants will be smaller, but still delicious.

Suggested Varieties

Although there are varieties of tatsoi, you will probably only find seed labeled simply Tatsoi and they can have either white or green stalks. There is a nice savoyed variety that grows a little larger and more upright. Again, I've only found it for sale as Tatsoi Savoy, but I have seen 'Yukina Savoy' mentioned elsewhere.

• 'Black Summer' - Plant in fall and harvest into winter. Very dark leaves.
• 'Ching-Chiang' - Quick growing dwarf that can handle early spring weather.
• 'Joi Choi' - A medium-sized plant with good bolt resistance.
• 'Mei Qing Choi' - Dwarf variety with quick growing (35 days), tight, green heads.
• 'Win-Win' - Extra large, dense heads. Slow to bolt.

Uses

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

Growing Tips

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.

Planting: You can direct sow or start seed indoors about 4 - 5 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 4 - 8 days.

Plant seed 1/4 - 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 6 - 8 inch spacing.

Fall grown tatsoi usually does better than seed sown in the spring. Besides the greater chance off the seedlings experiencing cold temperatures or frost, in the spring, which will cause them to bolt, there are also less insect pests in the fall.

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

Maintenance: Maintenance and care:

As with most leafy vegetables, tatsoi needs regular watering or it will bolt to seed. If your soil is rich, you should not need to feed the plants. Otherwise use a fertilizer high in nitrogen.

You can succession plant every couple of 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 4 years.

Pests & Problems

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. white flies and aphids are less of a problem.

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