Succulents mostly come from arid and dry regions that do not see rain very frequently. While it is true that some succulents are a bit touchy when it comes to being over-watered but we think that people tend to panic a bit too much when it comes to leaving succulents out in the rain.
Rain can kill and rot some sensitive succulents but the great majority will be fine. Succulents prefer potting mix that dries out between watering, but they are unlikely to die purely because of rain. Keep them away from flooded gardens, heavy soil, pots without drainage or too much shade.
Let’s have a closer look at what can tip succulents into rotting when it rains and how to prevent them from dying in too much rain.
In our experience, succulents planted in the garden always seem to love getting rained on and to date none of the 400 odd varieties that we grow in the ground have died from too much rain (having said that we do grow varieties that are sensitive to rain and will cover that below). The succulent gardens around our nursery are planted on a slope or raised where stagnant water is not able to drain away properly. We don’t add anything in our, what can only be described as, very poor soil yet the succulents live even during rainy spells.
We think that the secret is to plant succulents in spots where water can drain away easily so even if it rains for days on end, they are not submerged in water and as a result their roots not being able to get oxygen.
If you’re worried about the natural state of your soil (too clay-like or heavy) it can always be broken up and made more free draining by adding good quality potting mix, perlite or fine, composted mulch. Do not add sand as when wet, it can become too heavy and suffocate the roots.
For succulents to live happily outside never plant them where water has trouble draining after the rain and if you live in a subtropical/tropical/areas with lots of rain, help your plants by making the soil more breathable, adding the above mentioned potting mix, perlite or mulch.
Many succulents need quite a bit of sun exposure to grow and be healthy. The amount of sun can vary, but very few succulents will successfully grow and maintain their shape in deep shade. The great majority of succulents also dislike humidity and if this is compounded by them being in shade, succulents could easily rot after rain.
It is best to plant succulents in a sunny position as this will help to dry out soil after rain and will also prevent dampness, unless they are shade- loving succulents such as haworthias, gasterias etc. Which will need to be shielded from the sun.
In the ground succulents will survive even in poor soil but it is a different story when it comes to pots. The roots are limited by the pot and cannot spread or grow deep to find nutrients, more stable temperature or air. All they need has to be found in the pot.
Some succulent or other (usually very cheap) potting mixes can be too heavy due to a lot of sand that almost becomes airless and heavy when it gets wet and this can suffocate the roots. Many low quality mixes also have too much organic matter which succulents do not like. They would be fine in the ground in these kind of conditions, but not in pots.
Even worse than bad potting mix in a pot is plain garden soil. Despite succulents growing happily in the garden, it is very likely they will not grow too well in plain ol’ garden soil in pots. Some extra hardy varieties such as graptopetalum paraguayens or crassula ovata can survive, but their growth will be slow. The reason for gardens soil not being suitable for pots is that it, like sand, simply becomes too heavy when wet and if it rains a lot there is a good chance that its inability to drain fast enough and not leave sufficient air for the roots will rot the plants.
What a good quality, airy and light potting mix does is to provide air pockets, even when its raining heavily and not crushing the roots. We found that our nursery succulents (including cacti/ plants classed as very sensitive to over-watering) always survive rainy periods without a problem. Apart from a few cacti like Euphorbias, the Bishop’s Cap Cactus and some hybrid Echeverias & other ( we will list below) all our plants are grown out in the open and there is nothing to keep the rain out. We think our succulents live through this due to the fluffly, light and very well draining potting mix we use.
It is hard to get a perfect quality potting mix and as mentioned above, even some succulent & cacti potting mixes can be too heavy. A simple way to fix this and make any mix airy is to add perlite/ pumice. Whatever you do, do NOT add more sand.
You can get away (we do not recommend this) with planting succulents in pots without drainage holes if they are made out of concrete/terracotta or if they are under cover. Concrete and terracotta are porous and will eventually let the water evaporate through the walls of the pot. If it rains heavily for extended periods though, the chances are your succulents will drown and rot as the walls are not porous enough to let great amounts of water through.
The safest bet is to just go for a pot with a drainage hole. If you really really really like a pot that has no hole, there is always a possibility to drill one in. Concrete and terracotta pots are easy to drill through with a bog standard drill bit. Ceramic pots might need a diamond tip or masonry drill bit so the pot does not crack.
If you have a pot in the open, always plant in pots with a hole.
When succulents are cut for propagation they should be left in a dry environment for at least 24 hours so the wound heals. If they are planted straight in the wet soil and while it rains, some varieties can rot.
After the cuttings have healed for a day or two they can safely go outside in the open and should survive even if it rains.
Some (only a very slim minority) succulents are a bit more touchy when it comes to water and can indeed rot when left in wet soil/ potting mix for too long, no matter how well it drains.
To date we only found a few plants that need to be protected from rain and they include:
In our nursery, they live in a small polytunnel with a plastic cover to keep the rain out. However, we do not grow all the succulents in the world and there are new hybrids being produced frequently, so this list of plants may grow as we acquire new plants.
It is always good to be cautious, especially when you are growing expensive & rare succulents. If you are worried they are going to die during rainy spells let them get wet as they will like the fresh rain and then bring under cover to give them a chance to dry out completely.
We still stand by the claim that most succulents are likely to be ok in the open if the above is taken into consideration.