Indoor Cactus Care

NurtureNudge care guide · Updated October 2026

Cacti are the set-it-and-forget-it champions of the houseplant world — and almost every indoor cactus death is a death by kindness. Too much water, not too little, is what kills them. The trick is to think like a desert: long droughts punctuated by rare, drenching downpours. Get that rhythm right and a cactus will outlive nearly everything else you own.

Water: the 21-day rule (roughly)

Water deeply every three weeks or so — but only when the soil is completely bone-dry all the way down. When you do water, drench it until water runs freely out the drainage holes, then empty the saucer and walk away.

In winter, your cactus barely drinks at all. Many go semi-dormant: once every six to eight weeks is plenty, sometimes less. When in doubt, wait another week. A thirsty cactus wrinkles slightly and recovers with one drink; an overwatered one rots from the base up and doesn't come back.

Light: as much sun as you can give

Give your cactus the brightest window in the house — south-facing is ideal. Four to six hours of direct sun a day is the goal, not a luxury.

• Best: a sunny south or west windowsill with direct sun most of the day.
• Fine: bright indirect light, though growth will be slower and less compact.
• Avoid: dark corners and north-facing rooms — the plant will stretch pale and weak reaching for light it can't find.

One caution: acclimate new cacti gradually. Don't move one straight from a dim shop shelf into blazing sun in a single afternoon — give it a week of bright-but-indirect light first to avoid sunburn.

Feeding and upkeep

Feed sparingly: a diluted cactus fertilizer once a month in spring and summer, and nothing at all in fall and winter. Cacti evolved in poor soil — extra food does more harm than good.

Gritty, fast-draining soil is non-negotiable. Standard potting mix holds far too much water; use a dedicated cactus mix or amend regular mix with perlite or coarse sand. Terracotta pots beat plastic every time — the clay breathes and dries the soil faster. Repot rarely, and handle with tongs or folded newspaper: the spines are not decorative.

Troubleshooting: the five common problems

1. Mushy, translucent base: Overwatering and rot. Stop watering immediately. If the rot has spread up the stem, the plant is likely gone — salvage any firm, healthy cuttings and let them callus before replanting.
2. Tall, pale, stretched growth: Not enough light (etiolation). Move it somewhere sunnier. The stretched part won't shrink back, but new growth will come in compact.
3. White cottony patches: Mealybugs. Dab each one with rubbing alcohol on a cotton swab and isolate the plant until they're gone.
4. Wrinkled and deflated in winter: Usually normal dormancy thirst, not an emergency. Give it a light drink, but don't resume the summer schedule until spring.
5. Brown, corky patches at the base: Often just natural corking as the plant ages — harmless. If the patch is soft or spreading, treat it as rot.

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