Coriander

Botanical name : Coriandrum sativum

Common name : Coriander, Cilantro

Growing for seed

Coriander flowering is initiated by hot weather. Because it can be quick to flower it is generally grown in cooler seasons or alternatively it is succession planted to ensure leaves for cooking are available when required.

When growing for seed it is helpful to begin plants during cooler weather so that they can attain a good size before bolting as a larger plant is more likely to produce larger, stronger seed. Depending on the local climate they can be sown in late autumn or winter to go to seed when the weather warms up or sown in early spring as long as they can attain a good size before hot weather arrives to start the flowering phase.

Coriander plants that are grown for seed do not require large spacings and will happily grow and flower at around 15cm spacings.

While coriander is cross-pollinated by insects there are not many named cultivars, so home gardeners may decide not to worry about isolation distances for their home saved seed.

Selection

Plants that bolt early should be avoided as seed stock. It can be useful to grow a reasonable number of plants so that any that bolt before the others can be removed.

Avoid harvesting seeds from very small, weedy plants.

Harvest

As the round seed matures it turns from green to brown or tan. Once mature it is easily detached from the plant and will fall into the garden if not harvested promptly.

Regular checking and prompt harvesting is required at the seeds approach maturity as seed can easily shatter into the garden. Whole plants or stems can be cut and laid on tarps or put into paper bags or pillowcases and left in a protected area to dry.

Processing

Processing the seed is relatively easy as the seed freely detaches from the plant when mature. Threshing the seed by either walking on the cut plants or beating the stalks will see the mature seed quickly dropping onto a collecting tarp. Seed can the sieved and winnowed to remove unwanted frass.

Storage

After processing it is a good idea to keep the seed in a paper bag in a dry location for another few weeks to ensure that any moisture being held in the seed by the plant material has a chance to dry off.

There is a fair likelihood that insect pests will have laid their eggs in or on the seed. To stop them in their tracks one of the easiest methods of control is to freeze the seed for a few days. To do this the seed must be absolutely dry first. It then must be placed in a sealed airtight container – like a glass jar – and left in a freezer for 48 to 72 hours to kill pests and their eggs.

Seed is best stored in an airtight container where it is dark, cool and dry.

Contributors

Liz Worth, Nellie Pryke