How often to water coriander

The interval

Coriander is watered more often than almost anything else in this journal. Count on about every 3 days in the warm part of the year and about every 8 days in the cool part. The warm part is late spring and summer, roughly May to September in the northern hemisphere and November to March in the southern, when a pot can dry in a day or two. The cool part is autumn, winter and early spring, when the pot stays damp for the best part of a week.

Go by touch rather than the number, and look at the pot every day in warm weather. Push a finger into the compost. The top 2 cm should feel damp, never dusty and never sodden. Lift the pot as well. A deep pot of moist compost is heavy and one that has dried is surprisingly light. The Royal Horticultural Society says plants in containers dry out faster than plants in the ground and should be checked daily.

The method is keep-moist, which means small, regular drinks and not the soak and dry of a succulent. Water gently at the base of the plants until the compost is damp throughout and a little runs out of the bottom. Never leave the pot standing in water, because the RHS notes that container coriander dislikes waterlogging. Humidity is medium for this plant and nothing needs doing about it.

Overwatered coriander yellows at the bottom, and small flies hover over compost that never dries. Underwatered coriander browns at the leaf edges and, worse, it bolts. The RHS names heat and dryness as the triggers for early flowering, and a plant that has dried out once reads it as the end of its season. The answer is to sow again, not to water harder.

The thing particular to coriander is the taproot. It sends one long root straight down, which is why it resents transplanting and does best in a pot at least 25 cm deep, sown where it is to grow. A pot that is too shallow brings on bolting. In summer give it afternoon shade, and water as soon as the compost dries, not when the plant shows it.

Related guides

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