Tatsoi

Tatsoi is a true winter vegetable and usually comes through lowland winters in Central Europe outdoors without protection: the flat leaf rosette lies against the ground in frost and so protects itself, and snow as a blanket helps further. Sow it directly in the bed from August to mid-October and keep harvesting through the cold months; in severe, lasting frost you can lay fleece over it or put a cold frame on top to extend the harvest. For survival, though, this is not necessary.

You propagate tatsoi exclusively by sowing. As a short-lived leaf vegetable it forms no runners, bulbils or woody shoots. You can sow straight into the open ground or start it under cover: in spring you begin pre-sowing on the windowsill from mid-March and plant the young plants out in the bed from mid-April; alternatively you sow directly in spring from mid-April to mid-May. For the main harvest in autumn and winter, sow directly at the final spot from July to September; the plants then bolt less quickly because the days are getting shorter. Sow about 0.5 to 1 cm deep with 25 to 30 cm between rows, and thin later to 10 to 15 cm in the row. Germination takes about a week at around 15 to 20 °C. Tatsoi is very frost-hardy (reliably well below −10 °C, even lower depending on snow cover) and suits late autumn and winter growing under horticultural fleece or in a cold greenhouse. Seeds are easy to save yourself: tatsoi is biennial. If you let a few plants that have overwintered in a mild winter flower in the second year, you can harvest the pods shortly before they burst and dry them further. Note that F1 hybrid varieties do not come true from seed; for stable characteristics, use open-pollinated seed.