Every autumn, growers of potted succulents face the same question: what needs to come indoors, and where should it go? The answer depends less on cold alone than on the combination of cold, wet and low light. Most winter losses share one cause: a potting mix that stays damp while the plant is no longer growing.
This guide explains how to overwinter succulents in containers: which plants to bring in, when, where to keep them, how little to water, how to protect the pots that stay outside, and how to move everything back out in spring.
Which succulents to bring in and which to leave outside
The first criterion is the cold hardiness of each species. The Royal Horticultural Society (RHS) hardiness ratings are a practical reference because each one corresponds to an absolute minimum temperature range: H1b, 10 to 15 °C (50 to 59 °F); H1c, 5 to 10 °C (41 to 50 °F); H2, 1 to 5 °C (34 to 41 °F); H3, -5 to 1 °C (23 to 34 °F); H4, -10 to -5 °C (14 to 23 °F); and so on up to H7. In North America, the USDA zone system serves the same purpose; our article on hardiness zone systems around the world explains how they compare.
For example, the RHS rates Euphorbia milii H1b, Aloe vera and Aeonium arboreum H1c, and Crassula ovata, Echeveria elegans and Agave americana H2. These ratings are set for British conditions and are cautious, but they show the relative sensitivity of each plant well.
- Must come indoors: tropical and subtropical succulents (rated H1 by the RHS), such as Madagascan euphorbias, Adenium, Pachypodium, most aloes and Aeonium.
- Need frost-free shelter: H2 plants, which tolerate cool temperatures but not frost (many Echeveria, Crassula ovata, many cacti).
- Can stay outside, sheltered from rain: hardy species such as houseleeks (Sempervivum), hardy stonecrops (Sedum), some Opuntia, agaves and mountain yuccas. Our guide to cold-hardy succulents covers these species in detail.
The second criterion is moisture. A plant in a container is more exposed than one in the ground: its roots lack the insulation of a mass of soil, and the whole root ball can freeze. Above all, a pot that receives rain for weeks on end stays saturated. The RHS notes that rot is linked to excess water combined with cold, and that slightly dehydrated plants are hardier. Even hardy species benefit from rain protection in winter.
When to bring succulents indoors
There is no fixed date: night temperatures decide. Bring in the most tender plants (H1b, H1c) when nights regularly drop below about 10 °C (50 °F). H2 plants can wait until the first frost is forecast. As a rough guide, where frost is regular most tender succulents need to come under cover each winter, while in frost-free coastal areas many can stay outdoors provided they are kept dry.
Prepare a few weeks ahead:
- Water less often from late summer, so plants go into winter with dry potting mix.
- Stop feeding: the RHS recommends feeding indoor cacti and succulents from April to September only.
- Clean up: remove dead leaves, debris and weeds, which hold moisture and shelter pests.
- Inspect every plant, including leaf axils, the underside of rosettes and the stem base, for mealybugs. Treat and isolate any infested plant before it joins the others.
- Move plants in dry weather, in dry, clean pots, with no saucer full of water.
Where to overwinter succulents
The ideal place combines three qualities: cool, bright and dry, moving air. Together they allow a true rest: the plant slows down, uses little water and does not stretch.
A cold or frost-free greenhouse
This is the best option for a collection. A greenhouse kept frost-free, with a small thermostatic heater for the coldest nights, gives maximum light and low temperatures. Ventilate whenever the weather allows, because condensation and stagnant air encourage mould. The most tender plants (H1b, H1c) need a heated greenhouse rather than one that is merely frost-free.
A conservatory or garden room
An unheated or lightly heated conservatory works very well. Watch for frost on clear nights if it is poorly insulated, and for overheating on sunny days, which wakes plants up in midwinter. A minimum-maximum thermometer is very useful.
A cool, bright room
A lightly heated bedroom, a glazed stairwell, or a frost-free garage with a large window: any cool room with good light will do. A garage or cellar without windows is only suitable for a few days during a cold snap, because plants stretch without light even when they are cool.
A heated living space
In a living room at 19 to 20 °C (66 to 68 °F), plants do not really rest: warmth drives growth that winter light cannot support, which leads to long, pale stems. If this is your only option, place pots against the brightest window, away from radiators, add a grow light if possible, and water sparingly.
Light, temperature and watering in winter
Temperature. For cacti and most indoor succulents, the RHS recommends night temperatures of about 8 to 10 °C (46 to 50 °F) during the rest period. The cooler the plants are kept, the drier the potting mix must be.
Light. Give as much light as possible: a couple of metres back from a window, a plant receives far less light than it seems. Turn pots from time to time.
Watering. From about November to early March, the RHS advises minimal or no watering, only enough to stop plants shrivelling. Kept cool, below about 10 °C (50 °F), most cacti need no water at all over winter. Seedlings and small pots, which have few reserves, can have a little water in midwinter on a sunny morning. When in doubt, do not water: a slightly shrivelled plant plumps up again in spring, while a rotten one is usually lost.
Fertiliser. None at all in winter. Feeding a resting plant achieves nothing and can encourage soft growth.
Exceptions. Not all succulents rest in winter. Aeonium grow mainly in the cool season and rest in summer (see our guide on how to grow aeoniums): keep them frost-free, in full light, with light watering. Christmas cacti (Schlumbergera) flower in winter and then need warmth and regular watering, according to the RHS.
Protecting pots that stay outdoors
Large containers that are hard to move, and hardy species, can stay outside if they are protected above all from rain.
- Keep off the rain: place pots under eaves, against a wall, under an awning or a light roof of clear panels. The RHS notes that plants at the foot of a wall or under an eave stand a better chance of survival.
- Raise the pots on pot feet, bricks or blocks so water drains freely and the base does not sit on cold, wet ground.
- Insulate the container during cold spells: hessian or bubble wrap around the pot helps stop the roots freezing. Thick terracotta and large volumes freeze more slowly than small pots.
- Use horticultural fleece wisely: it gives a few degrees of protection on frosty nights, but it holds moisture if left on in the rain. Put it on for cold nights and take it off afterwards. Do not wrap tightly: the RHS stresses the need for air circulation.
- Let pots dry slightly before protecting them, and do not water plants that are sheltered from rain.
The same applies to large agaves in containers, often too heavy to move; our guide to growing agaves in pots covers the containers and mixes that make winter easier.
Pests during overwintering
Mealybugs are the main problem for succulents brought indoors. The RHS says glasshouse mealybugs are found mainly on greenhouse plants and houseplants, especially cacti and succulents, that they thrive in warm conditions and remain active all year indoors. Look for fluffy white wax in the leaf axils. Some species, root mealybugs (mostly Rhizoecus), live in the potting mix and are only seen when you unpot the plant.
- Inspect plants before bringing them in, then every two to three weeks.
- Quarantine new plants: the RHS recommends keeping them isolated for at least a month.
- Remove small colonies with a cotton bud dipped in surgical spirit, testing a small area first on species with delicate skin.
- A plant that declines for no visible reason is worth unpotting in spring to check the roots.
Biological controls such as the ladybird Cryptolaemus montrouzieri need warmth; the RHS considers them likely to succeed mainly from May to September, so they are of little use in a cool winter shelter.
Moving plants out in spring
Move plants back outside once the risk of frost has passed and, for the most tender ones, when nights stay above about 10 °C (50 °F). Resume watering gradually: one light watering first, then normal watering as growth restarts. Feeding resumes with growth, from April.
The trickiest step is sun exposure. After months behind glass or under weak winter light, the plant’s skin is no longer used to direct sun. A plant moved straight into full sun can develop whitish, then brown patches within hours: this is sunburn, and the damage is permanent. Start plants in bright shade or under shade cloth, then increase exposure over two to three weeks, beginning with morning sun.
Common mistakes
- Watering as in summer a plant that is cool and resting: the main cause of winter rot.
- Overwintering warm and dark: the plant stretches and weakens.
- Bringing plants in too late, after a first frost, or leaving a saucer full of water under the pot.
- Leaving a hardy plant in the rain all winter, relying on its cold tolerance.
- Bringing plants in without inspecting them and spreading mealybugs through the collection.
- Moving plants straight into full sun in spring.
Summary table by plant group
This table gives general guidance; always check the hardiness of the exact species you grow. The RHS ratings quoted apply to the species named.
| Group | Where to overwinter | Winter watering | Notes |
|---|---|---|---|
| Desert cacti (Mammillaria, Echinocactus, Ferocactus…) | Cool and bright, nights around 8-10 °C (46-50 °F) | None when cool | A cool, dry rest helps flowering |
| Epiphytic cacti (Schlumbergera, Rhipsalis) | Warm indoors, bright light without scorching sun | Regular while flowering | Different cycle from desert cacti |
| Opuntia and hardy cacti | Outdoors, sheltered from rain | None | Protect from wet rather than cold |
| Agaves | Depending on species: outdoors under cover or frost-free | None or almost none | Agave americana: H2 (RHS) |
| Aloes | Frost-free, bright; warmer for tender species | Very little | Aloe vera: H1c |
| Aeonium | Frost-free, full light | Light but regular | Cool-season growers; A. arboreum: H1c |
| Succulent euphorbias | Warm, bright | Very little | Euphorbia milii: H1b; irritant sap |
| Crassula | Frost-free, bright | Very little | Crassula ovata: H2 |
| Echeveria | Frost-free, very bright | Very little, keep water off rosettes | Echeveria elegans: H2 |
| Hardy Sempervivum, Sedum | Outdoors all year | Natural rainfall, free-draining pot | Raise pots off the ground |
For year-round care, see our guide on how to care for succulents.
Frequently asked questions
At what temperature should I bring succulents inside?
The most tender ones (aloes, Aeonium, tropical euphorbias) when nights regularly fall below about 10 °C (50 °F); plants that tolerate cool but not frost, before the first frost is forecast.
Should I water succulents in winter?
Very little or not at all when they are kept cool. A light watering is only useful if a plant is clearly shrivelling, or if it is kept warm. Aeonium and Christmas cacti are the exceptions.
Why are my succulents stretching in winter?
This is etiolation, caused by lack of light and often made worse by warmth. Move them closer to the window, lower the temperature if you can and reduce watering. The stretched part will not recover, but new growth will be normal.
Is horticultural fleece enough to leave a pot outside?
Not for a frost-tender species. For a hardy species, horticultural fleece helps on frosty nights, but rain protection and a well-drained, raised pot matter more.
When can succulents go back outside?
After the last frost, once nights are mild, acclimatising them to sun over two to three weeks to avoid sunburn.
Sources
- Royal Horticultural Society. How to grow houseplant cacti and succulents (Growing Guide). rhs.org.uk
- Royal Horticultural Society. How to grow hardy cacti and succulents (Growing Guide). rhs.org.uk
- Royal Horticultural Society. RHS hardiness ratings. rhs.org.uk
- Royal Horticultural Society. Glasshouse mealybugs. rhs.org.uk
- Royal Horticultural Society, plant profiles: Aeonium arboreum, Aloe vera, Agave americana, Crassula ovata, Echeveria elegans, Euphorbia milii (hardiness ratings). rhs.org.uk/plants
- USDA Agricultural Research Service. USDA Plant Hardiness Zone Map. planthardiness.ars.usda.gov