Succulents have a fantastic ability to store water in their stems and leaves which will see them last without water longer than the majority of other plants. But how long is that, exactly?
Unfortunately, there is no straightforward answer as factors like the type of succulent, seasons, temperature, pot size, the age of the plant, position (indoor/ outdoor/ shade/ direct sun). Generally speaking, most succulents should survive for over a week without any water whatsoever, though a lot of succulents will go without water for much, much longer.
In this article, we will have a look at how the above mentioned factors influence the length of time succulents can survive without a single drop of water.
There are many succulent genera and species which are often very different in looks and needs. The easiest way to determine how long a succulent can go without water is to look at how much water it can store. In most instances, the type of succulent that can survive without water the longest will have thick leaves and stems (there are exceptions such as Crassula Ericoides). The water stored in the swollen parts will slowly be made available to the plant, and as it is used, the plant will start shrivelling. There will be other changes taking place, like losing bottom leaves and growing even thicker and more compact. In some succulents, this process can take over 3 months. Some of the more common succulents that can go without water the longest are Graptopetalum Paraguayens (and many other thicker leaved Graptopetalums), some Echeverias such as the Albicans or Elegans, many Crassulas (Crassula Ovata and its hybrids all have thick stems and branches that can hold a lot of water), some Senecios (Serpens, Crassimus etc.), many Graptoverias, Graptosedums, Sedeverias, Sedum Rubrotinctum or Portulacaria Afra. Then there are cacti which have completely adapted life on minimal water. Many of these amazing succulents can last for over 6 months without water.
Succulents that will last the least amount of time without water are plants with thinner leaves and stems such as many Sedums (especially Sedum Little Missy/Mr, Acre), some Echeverias like Glauca, Orostachys Iwarenge, many Rhipsalis species & many Epiphyllums.
The seasons affect succulents ability to go without water in two ways. Firstly the temperature and secondly natural cycles (growth and dormancy). When it comes to temperature, it is quite obvious that hotter it gets more water evaporates from the soil and also the plant itself. As a result, succulents will need to be watered more often than during the cooler months. Here west of Sydney, Australia temperatures can easily tip over 40C (104F) many times during late spring and throughout summer. Succulents in our nursery are watered twice or three times per week during hot spells without any rain (although the plump ones would last over a week). In late autumn and throughout winter we water once every 1-2 weeks in the absence of rain (the temperature can still reach about 20C (68F) here in winter during the day, but can drop to 0C ,and it tends to be windy, which aids evaporation. In many other parts of the world with a colder climate, succulents will not need to be watered for most of the winter.
Natural cycles affect the growth and times of the year when succulents will go dormant. For the majority of succulents, dormancy happens in winter, but some like Aeoniums are dormant in summer. Winter dormant succulents can last without water for a long time (nearly whole 3 months depending on the climate) while summer dormant succulents should be watered every now and again as they can dry out too much during heatwaves.
Succulents grown in pots will not last as long without water as their counterparts planted in the garden where their roots can tap into cooler and more moist soil. Water can evaporate a lot quicker from a pot, especially if it is dark coloured and placed in the sun and so pot plants will need to be watered more often.
Furthermore, pots that are smaller hold less water than larger pots. If a succulent is in a small pot, it will go without water for less than plants in bigger pots.
In most instances older, bigger and established plants can go without water for considerably longer than younger, smaller plants. Baby succulents (offsets or cuttings) with small roots will almost need to be watered every other day until they establish. Large, old plants like, say, a meter high Crassula Ovata will last a couple of months before showing signs of needing water.
Young plants will be particularly prone to drying out in summer and should be watered as soon as the potting mix dries out.
Where the succulent lives will play a big part in its need for water. Succulents outdoors, in full sun will not last as long without water as plants grown in part shade or filtered light. Please keep in mind that most succulents (not all though- it is good to know your succulents here) need at least a few hours of sun to stay compact, colourful and healthy. While the sun is important for the majority of succulents, it can also dry them out quicker and even burn the more sensitive ones. Keep an eye out for signs of stress like leaf shedding and shrivelling.
The best place to grow most succulents is under 30% shade cloth or in morning sun and afternoon shade (especially in summer). They will last longer without water and will also be protected from sun’s rays at their afternoon hottest.
Now let us have a look at indoor vs outdoor position. I would first like to state that the vast majority of succulents will struggle indoors unless grown in a sunroom or under good quality growing lights. There are succulents such as Sansevieria, Haworthia, Gasteria, Epiphyllums or Ceropegia that will grow indoors, but they will need a bright spot to grow well. Because it is not as airy indoors, water will not evaporate fast, and succulents will last much longer without being watered (2+ weeks).
The best rule, in our experience and opinion, is to water when the potting mix has dried out. Succulents should never have wet feet for long and the potting mix will need to be well-draining and airy. There are exceptions of course. Some succulents have higher water tolerance than others. To help understand this topic better, you can read ‘Can Rain Kill Succulents’ which explains how water can affect different succulents.