Coriander

Origin & history

Coriander comes from the eastern Mediterranean and the Near East and is among the longest-used spice plants of all — seeds have been found in Egyptian burial chambers. Its name derives from the Greek “koris”, the bedbug: that is how the Greeks described the smell of the foliage and the unripe fruit. In Germany only the seed was known for centuries, as a bread spice alongside fennel, anise and caraway; the fresh leaf arrived only with the Asian and Latin American cooking of recent decades. That some people find it soapy and others do not comes down to a variant of an olfactory receptor gene.

Varieties

Here too there are two breeding directions: leaf-coriander varieties such as “Confetti”, “Santo” or “Calypso” produce plenty of finely cut foliage and bolt late, while the seed types flower fast and in return yield abundant fruit. A packet without a variety name is almost always seed coriander and will be in flower after six weeks. What is in the packet, incidentally, is not a seed but a round split-fruit with two seeds inside — rub it lightly between your hands before sowing and the rows come up more evenly. So-called Vietnamese coriander is an entirely different plant and botanically unrelated to it.

Care

Coriander makes a taproot and will not tolerate being moved, so sow it straight into the bed and thin later to about ten centimetres. The most important job of the season is keeping it moist: a single drying-out in June is enough to send the plant into flower — a thin mulch layer keeps the soil cool and damp and does more good than frequent watering from a can. Do not feed it; on rich soil the foliage turns soft and the flavour goes flat. Once the first flower buds show, pinching them out consistently buys another week or two of leaf harvest.

What can go wrong

The trigger for bolting is not only heat but also day length — a sowing just before the solstice flowers fastest, which is why the good dates are April/May and once more in early August. As an umbellifer, coriander does not belong after carrot, parsley, dill, celery or fennel, nor twice running on the same bed; leave three to four years. Young seedlings are at risk from slugs, and aphids regularly settle on the flower heads in summer — pinching off the affected shoot tips is enough, and if you leave the umbels standing for a seed crop, hoverflies and ladybirds usually lend a hand of their own accord.

Harvest, storage & kitchen

Leaf coriander is best cut as a whole plant just above the ground while it is still not flowering; use it raw and add it to the dish only after cooking, because heat destroys the aroma entirely. Dried leaf is worthless, whereas frozen it keeps a great deal — and the root is a spice in its own right in Thai cooking and well worth using. Harvest the seed when the fruits turn beige but before the heads start shedding: cut whole umbels and dry them upside down in a paper bag. Freshly ground, your own coriander seed tastes markedly more citrusy than bought powder.

Frequently asked questions

When do you sow coriander?

Straight into the bed between 10 April and 10 August, a good centimetre and a half deep, which is deeper than most herbs. It takes two to three weeks to appear, and the first leaf picking comes six to eight weeks after sowing, from early June at the earliest.

What sort of spot does coriander need?

Partial shade and not too hot: four or five hours of morning sun is ideal, while full midday sun drives it into flower. The soil may be loose and on the lean side. In summer it does well in the light shade of taller neighbours such as beans or sweetcorn.

Is coriander winter hardy?

No. It takes a light autumn frost, but as an annual it will not sit out a winter. A sowing in early August still yields leaf into early October under fleece; after that the crop is over and you start again in April.

Are coriander flowers edible?

Yes, the small white flowers are edible and milder than the leaf, and they look good scattered over salads and soups. The unripe green fruits are usable too, tasting fresh and lemony.