How to grow coriander in a raised bed without it bolting

To grow coriander for its leaves in England, sow it directly into the bed in small batches every few weeks from late March to June, in a spot with some shade from midday sun in summer. Keep the soil moist, pick young leaves often, and expect each batch to bolt (run to seed) eventually: the trick is to have the next one coming on.

Coriander is one of the trickier herbs to plan, and sources disagree on several points. Sowstory treats its coriander plan as a lower-confidence profile for that reason. This guide sets out what the sources agree on, where they differ, and how to fit coriander into a raised bed.

Coriander at a glance

When to sow coriander

Coriander for leaves is best sown little and often. The RHS suggests sowing small batches every few weeks, outdoors from spring into autumn, with later sowings under a cloche or in a greenhouse. Seed company Suttons gives a tighter outdoor window of late March to the end of June, and Mr Fothergill's suggests sowing every two to three weeks for a continuous supply.

Sowstory plans leaf coriander into the bed from April to June, the window where most sources overlap. The south and coasts can start a little earlier; colder, northern and high gardens later. See what to sow in April and what to sow in May for the other crops going in then.

Sow direct

The RHS says coriander resents being transplanted, so sow it where it is to grow. If you do start it indoors, keep it in its pot until it goes out and disturb the roots as little as possible. Mr Fothergill's gives 14–21 days for seed to come up.

How to sow coriander

1. Prepare a small patch of fine, moist soil. Suttons recommends well-drained ground.
2. Make a shallow drill and sow seeds thinly, about 5 cm apart, as the RHS suggests for a leaf crop.
3. Cover lightly, label and water. Expect seedlings in two to three weeks.
4. Thin if needed so the plants you keep have room to bush out.
5. Mark your calendar to sow the next batch a few weeks later.

Coriander spacing in a raised bed

Spacing advice for coriander is inconsistent, partly because it can be grown for leaves or for seed:

The RHS gives no row spacing for leaf coriander, so Sowstory plans it as a small group of individual plants rather than rows, at the wider 20 cm. That gives room to cut from each plant and lets air move between them. With 3 to 12 plants per batch, a small patch resown every few weeks keeps the leaves coming.

The vegetable spacing chart lists the other herbs and vegetables you might grow alongside.

Where to grow coriander

Here the sources pull in different directions. Suttons recommends full sun and well-drained soil, while the RHS says summer leaf sowings prefer a spot shaded from midday sun, and Mr Fothergill's says its slow-bolting variety tolerates partial shade. Sowstory treats coriander as a crop that tolerates four to six hours of direct sun.

A sensible compromise is to sow spring batches in full sun and summer batches where they get some shade around the middle of the day. In England the midday sun is to the south, so the shady side of anything tall, such as a fence, a shrub or another bed of climbing beans, is its north side. If your only raised bed is in full sun all day, keep summer batches especially well watered. Coriander is short, so it does not shade anything itself.

If you want coriander batches fitted in around the rest of the bed, Sowstory places them, tells you how many plants fit and gives a month-by-month plan. It is coming soon to the App Store, and your first bed plan is free.

How to stop coriander bolting

Bolting is coriander's main problem: the plant runs to seed, sending up a flower stem instead of producing more leaves. The RHS lists the triggers:

• Hot, dry weather, the most common cause.
• Changes in day length as summer approaches.
• Adverse weather in general.
• Drying out in containers, which makes pot-grown coriander bolt more readily.

What helps:

1. Choose a slow-bolting variety. The RHS names 'Cruiser' and 'Calypso'; Gardeners' World names 'Calypso' and 'Leafy Leisure'.
2. Sow direct rather than transplanting.
3. Water in dry spells. The RHS says extra water during long dry periods helps prevent bolting, and Gardeners' World says dry soil makes coriander bolt.
4. Give summer sowings midday shade.
5. Sow every few weeks so a fresh batch is always coming on when the last one flowers.

Growing coriander under cover and indoors

Coriander does not have to stop when the outdoor window closes. The RHS sows it indoors from February and uses cloches or a greenhouse for autumn sowings, and Mr Fothergill's lists indoor sowing all year round. Pots on a windowsill work, but remember the RHS warning that container plants dry out and bolt more readily, so water them little and often.

Sowstory plans outdoor raised beds only, so its coriander plan covers the April to June outdoor window. Anything you grow under cover or indoors sits outside the plan.

A coriander year in England

Harvesting coriander

The RHS says leaf coriander can be ready in as little as 10 weeks from sowing. Pick young leaves any time once the plants are big enough, taking a few stems from each plant. Mr Fothergill's suggests three or four cuts per plant from its slow-bolting 'Calypso', and Suttons names 'Confetti' as a quick, cut-and-come-again variety.

Sowstory reserves the space for about 10 weeks per batch. Once a batch bolts, clear it and resow, or leave a few plants to flower and set seed if you want coriander seed for the kitchen.

Why Sowstory marks coriander as lower confidence

Sowstory's knowledge base flags coriander as a lower-confidence crop, and it is worth knowing why:

• Spacing: the RHS uses about 10 cm for bought plants and 20 cm only for seed crops, while a seed supplier gives 20 cm. Sowstory uses the wider figure.
• Layout: the RHS gives no row spacing for leaf coriander, so Sowstory plans individual plants instead of rows.
• Sun: one supplier recommends full sun; the RHS prefers midday shade for summer sowings.
• Timing: the RHS sowing calendar runs from February to October, partly under cover, while the outdoor windows from suppliers are much shorter.

So treat the plan as a sensible starting point and adjust to your site and the weather.

Coriander as a companion plant

The RHS mentions that coriander is sometimes said to deter insects from basil and parsley. That is a claimed effect rather than a proven one; see the companion planting chart for how it compares with better-evidenced pairings. Suttons advises keeping coriander away from fennel. If you grow basil too, remember it needs more warmth than coriander; our guide on how to grow basil explains why.

For other easy first crops, see what to grow in a raised bed.

Sources

• RHS: How to grow coriander
• BBC Gardeners' World: How to grow coriander
• Suttons: How to grow herbs
• Mr Fothergill's: Coriander 'Calypso' seeds
• RHS: Three ways to use companion planting
• Sowstory knowledge base, release v1.4