Spring: waking up
As days lengthen, most desert cacti come out of winter rest and root activity resumes before top growth is obvious. RHS growing guidance puts repotting in spring, once a plant has outgrown its pot — root activity means a disturbed root system recovers faster than it would during rest, and the plant has the whole growing season ahead to settle in. That makes spring the workable window for repotting for most desert species, not a fixed date.
Bring light back up gradually rather than moving a plant that spent winter in dim conditions straight into full spring sun; our growing guide covers acclimating light generally. Resume watering as the mix actually dries and the plant shows it is using water again, rather than on the first warm day.
Summer: growth, heat and sunburn
This is the active growing season for the great majority of cacti kept as houseplants or in outdoor collections. RHS advice for this period is to water once the compost surface has dried and to feed roughly monthly with a potassium-rich or cactus-specific liquid feed through the growing months — treat that as a starting ratio and watch how your own plants respond rather than a fixed prescription.
Heat and light both peak now, and that combination is when sunburn shows up. UC IPM lists sunburn among the environmental disorders cacti are subject to, alongside the pathogens that cause rot. A plant that spent spring indoors or in shade can scorch if it is moved straight into unfiltered summer sun; increase outdoor or unshaded exposure in stages instead of all at once, and expect some pigmented or thin-skinned species to be more sensitive than others.
Autumn: tapering off
As temperatures and daylight drop, growth slows and water use falls with it. UC IPM's guidance is direct on this point: reduce watering of both landscape and containerized cacti in the fall to let plants move into dormancy. Watering on the same summer schedule into autumn, after growth has already slowed, is one of the more common ways a plant heads into winter with wet roots.
Taper feeding at the same time you taper water — active feeding into a slowing plant mostly just accumulates unused fertilizer salts in the mix rather than producing more growth.
Winter: rest, and the epiphyte exception
Most desert cacti want a cool, dry rest over winter. RHS describes cooler conditions with a modest night-time minimum and minimal or no watering — just enough, if at all, to stop the plant shrivelling — and notes that this rest period is what tends to encourage flowering the following season. Skipping a real rest, by keeping a desert cactus warm and lightly watered all winter, is a common reason a plant grows but does not flower.
Epiphytic cacti do not follow that pattern. Schlumbergera (Christmas cactus) and its relatives come from humid forest, not desert, and RHS's guide for it describes the opposite shape: regular water and warmth through spring and summer, then two separate cooler, drier rest periods — one in autumn to trigger buds, another after flowering — rather than one long dry winter dormancy. Treating an epiphyte like a desert cactus over winter, or the reverse, is the single most common seasonal mismatch we see.
RHS · How to grow Christmas cactus ↗ · Cambridge University Botanic Garden · Caring for cacti and succulents over winter ↗
A season-by-season table
A starting point for desert-type cacti in a temperate northern-hemisphere climate. Treat every column as approximate and adjust for your own climate, and remember Schlumbergera and other epiphytes run on the opposite watering rhythm through autumn and winter.
| Season | Water | Light | Feeding | Repotting | Watch for |
|---|---|---|---|---|---|
| Spring | Resume gradually as mix dries and roots wake | Increase gradually, not all at once | Begin as growth resumes | Best window for most desert species | Slow root recovery after repotting |
| Summer | Water once surface has dried; steady through active growth | Full sun for acclimated plants | Roughly monthly, potassium-rich or cactus feed | Avoid mid-heat repotting where possible | Sunburn on recently moved or shaded plants |
| Autumn | Reduce as growth slows | Natural daylight decline | Taper off | Avoid | Watering out of habit after growth has stopped |
| Winter | Minimal or none for desert species; just enough to prevent shrivel | Whatever natural light is available | None | Avoid | Cold combined with wet roots; epiphytes need the opposite routine |
Dying or dormant? A checklist
A resting plant and a failing one can look similar at a glance. Check more than one signal before acting.
- Firmness: a dormant plant stays firm to a gentle squeeze; a rotting one is soft or mushy, especially near the base.
- Color: dormant tissue may dull slightly but stays a consistent plant color; rot brings a darker, often wetter-looking discoloration, sometimes starting as a single spot that spreads.
- Smell: a resting cactus has no odor; a foul or sour smell points to bacterial or fungal rot.
- Roots: if you can check, dormant roots are pale and intact; rotted roots are dark, slimy or easily pulled apart.
- Shrivel: mild shrivelling with firm tissue underneath is usually just moisture loss during rest, not failure on its own.
UC IPM's list of cactus rot pathogens is a reminder that "it looks bad" is not a diagnosis by itself — several distinct diseases produce overlapping symptoms. If firmness and color both point to trouble rather than rest, Cactus health and Pests are the next stop.
Indoor, outdoor, greenhouse
This calendar assumes typical outdoor seasonal swings. Indoors, central heating can keep a desert cactus warmer through what should be its cool rest, which tends to blunt dormancy and, per RHS's Christmas cactus guidance on temperature drops, can also work against flowering for species that need a real seasonal cue. A greenhouse changes the picture again: glass can push daytime temperatures well above outdoor air even in winter, while still dropping close to outdoor lows overnight, so the "winter" column above may only loosely apply. Track your own thermometer and the plant's actual behavior over the calendar dates in this guide.