How often to water basil

The interval

Basil is watered more often than almost anything else in this journal. Count on about every 2 days in warm weather and about every 4 days in the cool part of the year, indoors on a bright sill. 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. The cool part is the rest of the year, when basil sulks and uses little. It dislikes cold, damp conditions, so the longer gap is a ceiling and not a target.

Go by touch rather than the number. Push a finger 2 cm into the compost: it should feel damp, never dusty and never sodden. Lift the pot as well. The Royal Horticultural Society says plants in greenhouses and containers need regular watering, and a pot of basil is noticeably light when it has dried.

The method is keep-moist, with water in the morning. The RHS explains that basil hates having wet roots overnight, and advises avoiding splashing the leaves. Pour at the base until the compost is damp throughout and a little runs out of the bottom, then empty the saucer. Humidity is medium for this plant, and ordinary room air is enough.

Overwatered basil yellows and rots at the base, and in seedlings the damage is damping off, the fungal collapse the RHS warns of, which overwatering encourages. Underwatered basil wilts, and dryness has a second cost: the RHS names dry conditions and overcrowding as triggers for early flowering, and flowering turns the leaf flavour. Pinch out any flower stem as soon as you see it, and harvest the shoot tips regularly to keep the plant bushy.

What is particular to basil is the supermarket pot. It holds many seedlings crammed together, which fight for water, dry the compost within a day and invite damping off, so split it into three or four pots with one plant per 15 cm pot. A plant given room and a morning drink lasts a season.

Related guides

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