Coriander has been used as a flavouring since ancient times – it was found in the tomb of Tutankhamen in Egypt, and the pungent leaves, also known as cilantro, have long been a feature of Asian cookery. It is again very fashionable and widely grown. But a little coriander goes a long way, and most children find its powerful flavour unpalatable.
Planning the crop
Coriander is easy to grow, and requires little attention. The most important ingredient for good growth is a sunny position. It will grow satisfactorily in any well-drained soil, but does best in soil that has been enriched with well rotted manure or compost. Grow it in small pots on the windowsill for a supply of fresh leaves.
How much to grow- If you enjoy the flavour of coriander leaf and you also intend to harvest the ripe seeds, then you will need at least a dozen plants. Coriander plants grow to about 45 cm high, with a spread of 15–25 cm.
Varieties– Although all varieties will produce leaves and seed, for varieties that are suited to leaf production and that delay flowering, try Long Standing, Chinese, Slow Bolting, Santo and 99057. Two other plant species that have a coriander-type flavour are also widely grown: Mexican coriander, or cilantro (Eryngium foetidum), and the perennial Vietnamese coriander, Vietnamese mint, or rau ram (Polygonum odoratum). Both tolerate hot, humid weather in districts where true coriander (Coriandrum sativum) is difficult to grow well. Quillquiña, or Bolivian coriander (Porophyllum ruderale), forms a shrubby plant that has an intense coriander fragrance with undertones of rocket.
Sow the seeds 1 cm deep in a well prepared outdoor seedbed in mid- to late spring. Usually, germination rates will be quite low; less than 50 per cent is common. To improve germination of home-harvested seed, rub the dry fruit to separate the seed halves, then soak in water for 72 hours before sowing. The optimal temperature for germination is 27°C, and germination begins in about four days. Thin the plants to 25 cm apart once they are large enough to handle. Use the thinnings as fresh leaves in salads and Asian cookery. Alternatively, sow a small pinch of seed in a plant pot. Bolting (running to flower) reduces the leaf harvest. Choose slow-bolting varieties and cover with shade cloth to give a longer leaf harvest.
Pests and diseases
Coriander is a relatively trouble-free crop apart from fusarium wilt and caterpillars. Autumn crops can be prone to powdery mildew.
Harvesting and storing
Use thinnings or pick leaves as needed. You can freeze the leaves for use in cooked dishes. For the seeds, your nose is the best harvesting guide. When the seed heads emit a pleasant, spicy odour – following their previous coriander leaf smell – cut them off and leave them to dry on trays in the sun or indoors. Or harvest when approximately half the seeds have changed from green to grey. Seed will shatter less readily from the heads in the morning. When they are dry, shake the seeds out of the seed heads or rub them off. Place them in an airtight container.