Succulent watering calculator

Why this gives you a day to check, not a day to water

More succulents die from kindness than from neglect, and the usual culprit is a fixed schedule — watering every Sunday whether the plant needs it or not. Succulents store water in their leaves precisely so they can sit out a long dry spell; the job is to imitate that, not to fight it.

So the method is soak and dry: when the soil is completely dry, water thoroughly until it runs out of the drainage hole, then leave it alone until the soil has dried all the way through again. A finger or a wooden skewer pushed an inch or two down tells you which of those two states you're in. This calculator only estimates when that's worth doing.

Where the numbers come from

The starting figures are the ranges in our own guide, How often to water succulents: roughly weekly for a plant in full sun in summer, every two to three weeks for one indoors, and monthly or less during winter dormancy. Pot material, pot size and soil then shift the estimate up or down, because a small terracotta pot on a sunny sill dries out far faster than a big glazed one in a cool room.

Treat the result as a reminder to go and look, not as an instruction. A plant in a draughty room, a heatwave, or a species that grows in winter will all move the real answer. The soil is the only reliable source.

If you're not sure, wait

An underwatered succulent — thin, wrinkled, puckered leaves — usually bounces back within a day or two of a good soak. An overwatered one, with soft translucent leaves and rotting roots, is much harder to rescue. The two failure modes are not symmetrical, which is why erring towards dry is the safer mistake.

• The soak-and-dry method in full
• Why is my succulent stretching? — if it's leaning and spacing out, that's light, not water
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