Cactus care in a small pot
A cactus is not a plant that needs nothing. It is a plant that needs a lot of light and almost no water, which people read as "leave it alone" — and then it etiolates into a pale cucumber.
Light
This is the part that fails first. A cactus indoors wants the brightest spot in the house: a south-facing window in the northern hemisphere, directly in the glass, for six hours or more. Anything less and new growth comes out stretched and thin, with wide spacing between the areoles — that stretched growth is permanent and never thickens back.
Windowsill heat is fine for cacti. Sunburn is not: a cactus moved straight from a dim corner to full afternoon sun in July will scar. Move it over two or three weeks instead.
Watering
Soak it, then let it dry completely. In practice:
| Season | Water | Signal |
|---|---|---|
| Late spring–summer (growing) | Every 2–3 weeks | Soil dry to the bottom of the pot |
| Autumn | Every 3–4 weeks | Soil dry, plant starting to slow |
| Winter (rest) | Every 5–6 weeks, or not at all | Soil dry for a week or more |
Water until it runs out of the drainage hole, then empty the saucer. Never leave the pot standing in water — that is the only way a cactus reliably dies. In a three-inch pot, tap the soil to check: it will feel light and dry within days of watering in summer.
In winter, many cacti want a genuine dry rest at cooler temperatures. That rest is what triggers spring flowering in species that can flower indoors at all.
Soil and pot
Gritty, mineral, fast-draining. A commercial cactus mix with 30–50% extra pumice or coarse perlite by volume is right. Ordinary potting soil holds water for days and rots the root crown.
Terracotta is the better pot here: it wicks moisture out through the walls, which in a small pot is a real advantage. Drainage hole required.
Repotting
Cacti like to be slightly root-bound, so repot only when roots come out of the drainage hole or the plant is visibly top-heavy. Go up one pot size, not three. Spring is the time. Handle with folded newspaper or tongs, not fingers.
What is actually wrong
- Pale, thin, stretched growth at the top — not enough light. Move it closer to the glass. The stretched part will not recover; you can cut it back in spring.
- Soft brown-black patches at the base — rot from overwatering or from sitting in a saucer. Stop watering, let it dry, and check whether the rot has reached the core; if it has, the plant is gone.
- Wrinkled, slightly deflated body — underwatered, which is far easier to fix. One thorough soak and it rehydrates within a few days.
- Corky brown patches on old growth — usually age or sun exposure, not disease. Cosmetic.
- No flowers, ever — most cacti sold as houseplants need a cool dry winter rest and strong summer sun to bloom. Some simply never will indoors. This is normal and not a care failure.