Why succulents struggle in winter

Cold weather on its own rarely kills a succulent. Most can handle a surprising amount of it. What they cannot tolerate is sitting in soggy, waterlogged compost whilst the temperature drops, and that combination is what finishes them off.

Here in the UK, our winters are rarely brutal cold snaps. More often they are long, damp and drizzly, with grey skies and moisture that never quite goes away, and it is the wet that makes winter care tricky.

Why wet compost is the problem

Succulents evolved in places where rain is rare and drainage is excellent. Their thick, fleshy leaves store water for dry spells, and they cope badly with constant dampness. Combine cold temperatures with wet compost and you have ideal conditions for root rot.

In their native habitats, succulents might face freezing nights, but they stay bone-dry. A UK winter gives them cold and wet at the same time. It's a bit like asking someone to sleep in a cold, damp cellar.

What happens in wet, cold compost

When a succulent's roots sit in waterlogged compost over winter, root rot sets in. Cold, wet compost suits fungi perfectly, and the roots turn mushy and black. Once the roots fail, the leaves fill with excess moisture, become translucent and turn to mush. Then the whole plant collapses, and by the time you notice, it is often too late to save it.

The frustrating part is how slowly this happens. A succulent can look fine for weeks and then collapse overnight, because the damage was done long before you saw any symptoms.

How to keep your succulents happy through a UK winter

1. Bring them indoors (but not just anywhere)

Unless you're growing genuinely hardy plants such as Sempervivums or Sedums, bring your succulents inside before the first frost. Don't just plonk them on a windowsill above a radiator, though.

Find them a bright spot, ideally a south-facing window, away from direct heat. Succulents can handle cool indoor temperatures (10-15°C is perfect). Give them light and dry air, and keep them away from stuffy central heating.

For most succulents, the ideal is 7-13°C at night and 12-18°C during the day. That keeps the plant frost-free without pushing it into unnatural growth.

Air flow matters too, so crack a window or let a fan blow over them whenever you get the chance.

2. Slash your watering to almost nothing

This is where most people go wrong. In winter, succulents are dormant or semi-dormant. They aren't growing, so they use hardly any water, yet many of us keep watering them on the same schedule as summer.

In winter, water lightly and infrequently: perhaps once a month, or even less.

Wait until the compost is bone-dry all the way through. Push your finger deep into the pot, and if there's even a hint of moisture, don't water. The leaves will tell you when they need a drink by starting to wrinkle slightly.

Many succulents in the UK may not need watering at all for the whole of winter. If the compost does become waterlogged, take 70% of it off and leave the plant to dry in an empty pot somewhere cool and bright. Once it has dried out, repot it into dry compost.

3. Use proper gritty compost (this is non-negotiable)

If you haven't already, now is the time to repot your succulents into proper gritty, free-draining compost. Standard multipurpose compost holds far too much moisture for winter.

To mix your own, use:

1/3 multipurpose compost (we highly recommend John Innes No. 2 for this)
1/3 horticultural grit or perlite
1/3 coconut coir

Or buy a bag of specialist cactus and succulent compost from your local garden centre. We would still mix in extra drainage, just for good measure.

A gritty top-dressing looks attractive, and it also keeps foliage dry, cuts down on fungus gnats and helps regulate moisture.

4. Give them good drainage

Every pot needs drainage holes, without exception. Even gritty compost needs somewhere for the water to go. If you have a succulent in a decorative pot without holes, either drill some or use it as a cache pot around an inner pot that drains.

After watering, don't leave any water sitting in saucers or outer pots. Empty them straight away.

If planting outside in the ground, raise your succulents on benches, tables or shelves so they are not in direct contact with cold or frozen ground. Growing them in a raised bed or rockery will give you better results.

5. Use horticultural fleece for frost protection

For succulents that can't come indoors, or that need extra protection, horticultural fleece makes a real difference. It is a breathable fabric that protects plants from frost, wind and harsh weather, and it helps keep the moisture problem in check at the same time.

Put fleece on when temperatures fall to 5°C or below. Light ground frost can occur at these temperatures, and young plants or tender varieties (such as variegated Aeoniums) can be damaged.

How to use horticultural fleece properly

Cut the fleece to size and drape it loosely over the plants so air can still move. Never press it tightly against the leaves.
Hold the edges down with pegs, rocks or weights so it doesn't blow away.
For added protection, put hoops or stakes under the fleece to make a mini greenhouse.
Take it off on warmer days when the sun is out, so moisture doesn't get trapped, then put it back in the evening.
Keep it dry. Fleece works best dry, so if heavy rain soaks it, dry it out to restore full frost protection.

Where frost persists and temperatures don't get back above 5°C during the day, you can leave the fleece on for days at a time. In full sun, plants get enough light through it to stay happy.

Why our fleece is different

We've used the same heavy-duty fleece on our own plants for years, and it has protected them well. At 60 grams per square metre, it's nearly 4x thicker than standard garden centre fleece, which means it:

protects against temperatures as low as -10°C
is durable enough to last for many years
resists rain, keeping plants dry underneath
is breathable, so you can leave it on through long cold spells
doubles as a hail shield when needed

At the end of winter, wash it, dry it and store it for next year. You can reuse it season after season, so it is very good value.

Voile d'hivernage de haute qualité | 60 g/m²

De £14.50

6. Watch for warning signs

Keep an eye out for these signs of trouble:

Translucent, mushy leaves point to overwatering damage.
Black or brown soggy stems mean root rot is spreading upwards.
Leaves that drop off easily are a sign of rot or extreme overwatering.
If the compost stays wet for days, it's time to repot into a grittier mix.
Outer leaves that look frozen or mushy after cold nights have frost damage.

If you catch these early, you may be able to save the plant by reducing water, improving drainage or taking healthy cuttings to propagate. With frost damage, wait until the plant thaws, cut off the damaged areas, then check it often to make sure rot doesn't set in.

The bottom line

Get your watering right, use gritty compost, make sure every pot drains, and protect tender varieties with a good fleece. Do that and your succulents will come through the UK winter looking good.

Many succulents actually need a cool, dry winter rest to grow well and flower come spring.