Succulents and cacti

A succulent is any plant that stores water in its leaves, stems or roots, which is a habit rather than a family: aloes, echeverias, jades, string of pearls and every cactus. They come from places where rain is an event rather than a pattern, and everything about how they are grown follows from that.

The single thing that decides whether a succulent thrives or slowly fails indoors is light. Not water, not soil, not the pot. These are plants from open ground under an open sky, and the brightest windowsill in a house is dimmer than the shade of the tree they grew under. Give them the sunniest spot you have and they will stay compact and coloured. Give them a coffee table two metres from a window and they will stretch, pale and lean, however carefully you water.

Soak and dry, and why

In the wild the roots get drenched and then dry out completely, often for weeks. Watering little and often keeps the compost permanently slightly damp, which is the one condition these roots have no defence against. Water thoroughly until it runs from the drainage hole, empty the saucer, and then do not water again until the compost is dry all the way through. A pot that still feels heavy does not need water.

Compost matters for the same reason. Ordinary potting mix holds too much water for too long. Mix it half and half with horticultural grit, perlite or coarse sand so it drains fast, and use a pot with a hole in the bottom. A terracotta pot dries faster than a plastic one, which is usually an advantage here.

The winter rest

Most succulents very nearly stop in winter. Short days and cool nights mean they use almost no water, and watering them on a summer rhythm through a dark December is the commonest way they are lost. The journal’s log slides the interval out across the season for exactly this reason, and for a plant like an aloe it will stretch from a fortnight in high summer to a month or more at the turn of the year.

A cool, bright, dry winter is also what makes many of them flower. A jade kept warm and watered all year rarely does. One kept cool and nearly dry from late autumn will often surprise you.