Watering, Repotting, Flowering & Beginner Tips
The cactus is the perfect plant for forgetful people. But “easy care” does not mean “no care at all” — and that’s exactly where many people go wrong.
The cactus has a reputation for being indestructible. And in fact, it does survive weeks without water, blazing sun, and neglect. But it has needs too — and if you understand them, it rewards you with growth and even spectacular flowers.
In Austria, cacti are strictly indoor plants (with the exception of a few hardy opuntias). In the Netherlands, they are grown in vast greenhouses and are among Europe’s best-selling plants.
Cactus at a Glance
Botanical: Cactaceae
Origin: The Americas (North to South America)
Species: over 1,700
Hardy: Few species (Opuntia)
Location: Full sun
Watering: Very little
Substrate: Cactus soil (mineral-based)
Difficulty: easy
Watering a Cactus
Watering a cactus is where most people go wrong — because of too much water, not too little. Cacti store water in their bodies and can go for weeks without watering. Waterlogging is a sure death sentence.
In summer (growing phase): Water every two to three weeks, once the soil has dried out completely. Water thoroughly, then pour away any excess water immediately.
In winter (dormant phase): Hardly water at all. A small sip once a month is enough. Some cactus experts do not water at all in winter — and the plants survive just fine.
Warning sign: A soft, mushy cactus has been overwatered. Remove it from the wet soil immediately, cut away any rotten parts, let it dry, and repot it in fresh, dry cactus soil. A shriveled, wrinkled cactus, on the other hand, needs water.
How to Get a Cactus to Flower
Many people don’t realize that cacti can flower — and spectacularly so. Some species produce blooms larger than the plant itself. But to do that, they need a cool, dry winter dormancy.
From November to February, keep the cactus in a cool place (5–10°C — an unheated stairwell, a cool bedroom, or a bright garage). Do not water or fertilize it. This cold period mimics winter in the desert and encourages flowering.
In spring, move it gradually to a warmer spot and start watering carefully. If all goes well, flower buds will form in spring or summer.
Tip: Christmas cactus (Schlumbergera) and Easter cactus (Hatiora) are exceptions — they come from the Brazilian rainforest, not the desert. They need more water, less sun, and will bloom without a cold dormant period.
Cactus Varieties for Beginners
- Echinopsis — spherical, fast-growing, and easy to flower. The blossoms open at night and have an intoxicating fragrance.
- Mammillaria — small, round cacti with beautiful spine patterns. They bloom reliably with a ring of small flowers.
- Opuntia (Prickly Pear Cactus) — flat, oval segments. Some species are even winter-hardy in Austria (O. humifusa survives down to –20°C).
- Schlumbergera (Christmas Cactus) — not a typical cactus, but easy to care for and reliably blooms in winter.
Repotting a Cactus
Repot into a slightly larger pot every two to three years. Important: use cactus soil — mineral-based, well-draining, and low in nutrients. Regular potting soil holds too much moisture and leads to root rot.
When repotting, use gloves or a thick newspaper to handle the cactus. Terracotta pots are better than plastic ones — they allow excess moisture to evaporate.
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Frequently Asked Questions About Cacti
In summer, every two to three weeks; in winter, barely at all (once a month or less). Only water when the soil has dried out completely.
Most cacti are non-toxic. The real danger comes from the spines — especially the fine glochids of Opuntia, which can lodge in the skin and are difficult to remove. Still, keep them out of reach of children and pets.
Yes, some Opuntia species are hardy down to –20°C and can be planted outdoors in Austria. Important: very well-draining soil (gravel, crushed stone) and a sheltered, sunny spot. Winter wet is more dangerous than cold.
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