How often to water calathea

The interval

A calathea is watered about every 5 days in the growing season and about every 9 days in winter, which keeps the compost lightly moist. The growing season is spring to early autumn wherever you live, so the northern and southern hemispheres sit on opposite halves of the calendar. The Royal Horticultural Society says to water moderately through the growing season and, in autumn and winter, to let the surface dry before watering again but never to let the compost dry out completely. It adds that careful watering is needed in winter to prevent oedema.

Push a finger into the compost and check that the surface is just dry before you water, and that the compost below it is still cool and damp. Weight is the second check. Lift the pot after a drink and again before the next one. A pot that has gone light means the pot has dried too far for this plant, and one that is still heavy when the interval is up is not ready.

An overwatered calathea yellows at the bottom, and in winter it can develop oedema, patchy, water soaked areas on the leaves, as the RHS describes. The NC State plant toolbox adds that overwatering can cause root rot. A thirsty calathea curls its leaves inwards, and the edges brown, whether the shortage is in the pot or in the air.

Water from the top, moderately, until a little runs from the drainage holes, and empty any water that collects in a decorative cover or the saucer. The plant is fussy about water quality. The RHS says all houseplants prefer rainwater, because mains water contains lime and chlorine, and the NC State plant toolbox says distilled water or rainwater is preferred because the fluoride in tap water can brown the leaf tips.

The thing particular to this plant is the humidity. Its needs are high, and a bathroom or a tray of damp pebbles under the pot matters as much as the watering, because the edges brown when the air is dry however regularly the pot is watered.

Related guides

How to tell whether a plant actually needs water

The finger, the weight, the leaf and the pot. Four ways to read a plant's thirst, and what overwatering actually is.

Rescuing an overwatered plant

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Watering through a southern winter

Winter in the southern hemisphere runs June to August, and houseplants drink far less then. How to read the soil, and why overwatering is the bigger risk.