How often to water Christmas cactus

The interval

A Christmas cactus is watered about every 8 days in the growing season and about every 14 days in winter. Growing season means the warm, bright months from spring to early autumn, roughly March to September in the northern hemisphere and September to March in the southern. Winter is the cold, short-day part of your own year, and in practice the plant flowers then, so the gap is a matter of keeping the compost lightly moist while it blooms. NC State Extension simply says to avoid overwatering.

Check by touch and weight. Push a finger 2 to 3 cm into the compost and water when it is dry at that depth. Then lift the pot. The Royal Horticultural Society notes that a drier pot feels lighter than a wet one, and a Christmas cactus in a snug pot is easy to judge this way. It is not a desert cactus, so do not leave it bone dry for weeks.

Water from the top with water at room temperature until water runs from the drainage holes, wait ten minutes and empty the saucer. NC State Extension recommends a moist, well-drained cactus or succulent mix. Humidity is medium for this plant. NC State Extension says it grows on trees in the coastal mountains of Brazil and that a bathroom suits it, though grey mould can follow high humidity with poor air circulation.

Too much water gives root rot, which NC State Extension names as a problem for overwatered plants. Too little, once buds form, makes them fall. NC State Extension lists moisture shortage among the causes of bud drop, along with too few dark hours, temperature swings and changes of light.

What is particular to this plant is its buds. Once they set, an irregular watering is one of the things that makes the plant drop them, so keep the watering even, choose the spot before the buds form, and leave it there. Feeding stops in late summer, and the plant flowers better slightly potbound.

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

How to tell overwatering from underwatering, how much root damage is recoverable, and the exact rescue steps once compost has stayed wet too long.

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.