Growing Coriander

Coriander is considered a herb when its leaves are harvested fresh and a spice when its seeds are the object of attention. It is not difficult to cultivate once you understand that it prefers cooler temperatures rather than the heat of summer. For that reason, warm and sub-tropical region gardeners should sow seed during mid-autumn to early winter, while southern and cold region growers need to have seed in the ground no later than mid-spring.

Soil Preparation and Sowing

Prepare the garden with well-rotted animal manure, rotted straw and compost, digging everything in to a fine tilth. Sow the seed in patches or shallow furrows to a depth twice the diameter of the seed. Water the ground well to promote the softening of the hard outer shell of the seed case. Coriander is notoriously slow to germinate, so label your sowings well and do not despair if the first seeds take up to three weeks to emerge.

How to Avoid Bolting

Prone to bolting (running to seed) when stressed, coriander needs to be grown without check. Keep the ground moist (I mulch the rows with pine needles at the same time as I sow, and water during dry spells.) If the weather takes a turn for the worse and temperatures become unseasonable, cover the plants with clear plastic spread over hoops of polythene pipe, supple willow wands or number 8 wire.

Failure to do this will see the leaves turn red, a sign that it is too cold for seedlings to take up nutrients. Stressed plants will also develop tough, tall central stalks rather than the lush, feathery foliage you are looking for. Bolting can also occur when seedlings are too crowded. Thin seedlings to 5 centimetres apart and feed weekly with liquid manure to encourage leafy growth.

Harvesting Coriander Seed

If it is the seed you are after rather than leaf, treat your plants as harshly as you wish and harvest the seed as it begins to dry on the plant. To do this, pull the entire plant from the ground, place it upside-down in a bag, and shake vigorously. Alternatively, pick in bunches and hang upside down over a carton or tray so the seeds drop in when fully ripe.

Complete seed-drying on a sunny window ledge, winnow off debris, and store seeds in sealed paper bags or envelopes. Seed can be used in cooking or re-sown in the coming season.

Related reading:
See our Vegetable Gardening page for more seasonal growing advice.