Cactus Care for Beginners

People buy a cactus expecting an indestructible houseplant, and a few months later they are holding a soft, browning stub. Clemson University’s Home & Garden Information Center calls cacti relatively easy to grow and well adapted to dry conditions in the home, but notes that too much water is one of the main problems, and that root and stem rots usually come from a mix that does not drain quickly or from watering too often.

A desert cactus wants bright light, a gritty free-draining compost, careful watering in summer and a cool, dry rest in winter. This guide follows the Royal Horticultural Society and Clemson.

Light: more than you think

The RHS says most cacti and succulents like bright light and suggests a sunny windowsill all year round, or even a spell outdoors in summer. Clemson says desert cacti need bright sunlight, ideally a south- or west-facing window where they get direct sun for several hours a day, and that artificial light may be needed to supplement natural light.

If you move a cactus outdoors for the summer, Clemson suggests partial shade for the first few weeks so it can adjust to the brighter light.

The exceptions: rainforest cacti such as the Christmas cactus, orchid cacti and rhipsalis like more frequent watering and semi-shade, so the RHS suggests an east- or west-facing window, or a south-facing one behind a net curtain.

Watering: less than anything else you own

Clemson calls watering properly the most important factor in growing cacti:

Growing season (March to September): cacti grow quickly; water them like any houseplant that likes to dry slightly between waterings.
Winter (dormant): let them get very dry between waterings, giving just enough to stop them shrivelling - usually a light watering every few weeks.
Never let the pot stand in water. Waterlogged compost quickly rots the roots.

The RHS gives the same winter advice: avoid watering during the winter rest, because it encourages weak growth, but give enough to stop the plants drying out so much that they shrivel.

Compost and pots: drainage is everything

Compost. The RHS recommends a very free-draining, gritty compost that will not get waterlogged: a ready-mixed peat-free cactus compost, or peat-free John Innes No 2 with up to 30 per cent grit or fine gravel by volume. For a decorative group, it suggests 2 parts John Innes No 2 to 1 part horticultural grit or sharp sand, topped with a mulch of grit or fine gravel. Clemson suggests commercial cactus mix or equal volumes of peat-based potting soil and very coarse sand or grit, and notes cacti prefer a rich soil as long as it drains freely. Our soil mix calculator helps you work out quantities for a pot of any size.
Pot size. Clemson notes cacti generally like to be slightly pot-bound. Both sources warn against too big a pot: the extra compost stays wet and can cause rot. Clemson suggests a pot only slightly larger than the current one.
Drainage. Use a pot that drains, and never leave it standing in water (Clemson).

Temperature and the winter rest

Clemson says cacti prefer 65-85°F (about 18-29°C) while growing, and that dormant cacti do best at 45-55°F (about 7-13°C) in winter; most tolerate normal house temperatures, but they are more likely to flower and thrive if kept cool in winter, for example in a sunny, cool room. The RHS suggests a winter rest with night temperatures of only 8-10°C (46-50°F), and notes central heating is not usually a problem as long as the plants are not close to radiators.

Feeding

Clemson suggests a low-nitrogen fertiliser such as 5-10-5 once a month from June to September, or a time-release fertiliser applied once in spring, and no feeding for newly repotted plants or desert cacti in winter.

Repotting and handling

When. Repot only when the roots have filled the pot or the plant has outgrown it, in spring (RHS); Clemson names April, as the plants begin their summer growth.
How. Repot into a container only slightly larger than the old one, and wait several days before watering (Clemson).
Protect your hands. Use heavy leather gloves or an oven glove, or wrap the cactus in several layers of folded newspaper (Clemson, RHS).
Prickly pears need extra care. Clemson warns that Opuntia stems carry tiny barbed bristles that are hard to see and can hurt more than the large spines; always wear heavy gloves.
Dust. The RHS suggests removing dust from prickly cacti regularly with a soft brush.

The mistakes that kill most beginner cacti

Too much water - the main problem Clemson names; root and stem rots follow overly frequent watering.
A compost that drains slowly - use a gritty, free-draining mix (RHS, Clemson).
A pot standing in water - waterlogged compost rots the roots quickly (Clemson).
Too little light - desert cacti need bright, direct light (Clemson, RHS).
Too big a pot - the extra compost stays wet and can cause rot (RHS, Clemson).

Pests

Clemson names aphids, spider mites and mealybugs as the main pests of cacti, and scale as harder to control. Check new plants for pests before you buy, and if you spray, use a product labelled for cacti and follow the label.

Beginner-friendly cacti

Clemson describes these as easy to grow:

Golden barrel cactus (Echinocactus grusonii) - a barrel-shaped body covered with heavy gold-yellow spines; Clemson calls it good for beginners.
Pincushion cacti (Mammillaria) - a large group of small, free-flowering cacti that are easy to care for, often so densely spined they look hairy.
Prickly pears (Opuntia), including bunny ears (Opuntia microdasys) - very easy to grow, but handle them only with heavy gloves.
Star cactus (Astrophytum) - easy-to-grow, spineless cacti with white flakes on the ribs.

Frequently asked questions

How often should I water an indoor cactus?

In the growing season, March to September, water like a houseplant that likes to dry slightly between waterings; in winter, give just enough to stop it shrivelling, usually a light watering every few weeks (Clemson).

Why is my cactus rotting at the base?

Clemson says root and stem rots usually come from a mix that does not drain quickly or from watering too often. Check the compost and the drainage, and water less.

Can a cactus survive in low light?

Desert cacti need bright sunlight; Clemson suggests artificial light if natural light is not enough.

Does a cactus need fertiliser?

Lightly: Clemson suggests a low-nitrogen feed once a month from June to September, and none in winter.

How big should a cactus pot be?

Only slightly larger than the old one. Cacti like to be slightly pot-bound, and too large a pot stays wet and can lead to rot (Clemson, RHS).

Sources

Royal Horticultural Society, How to grow cacti and succulents. Read 28 October 2026.
Clemson University Home & Garden Information Center, Indoor Cacti. Read 28 October 2026.

Recommended Gear on Amazon

Cactus potting soil - browse current options and reviews on Amazon.
Horticultural grit - browse current options and reviews on Amazon.
Cactus handling gloves - browse current options and reviews on Amazon.

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