More succulents are killed by wrong watering than any other reason, here we will try to explain the best methods, when and where.
Some tips and Advice on Watering Succulents Introduction As succulents become more popular around the world these drought tolerant plants have bought with them some confusion about how and when to water. As a general rule if in doubt don't water, most succulents have survived the passage of time in extremes of conditions normally being very dry. At certain times in the wild some species can receive the majority of the annual rainfall in the space of just a few days. As succulents come from various places around the world, the extent to which they go dormant, and the differing needs has a lot to do with their natural environment where they were originally growing and its seasonal fluctuations. As a basic rule most species can be divided into summer or winter growers, but this is not a hard, fast rule and many succulents will grow quite happily outside their normal parameters. The biggest influence is the minimum temperature tolerance, especially as we are all trying to be environmentally friendly and avoid using unnecessary heat. There are some succulents that are very cold hardy such as Sempervirens, while others are very tender with a good example being echeveria and here a minimum temperature of 5° C is recommended. It is equally important to remember that extremely high temperatures are as dangerous and plant tissue may burn leading to the death of the plant. Interestingly, both Sempervirens and echeverias both enjoy active growth during spring and autumn, when temperatures are more temperate and ideal for growth. Both species hating extreme heat at the height of summer, and in both cases plants may go into an enforced summer dormancy. Aeoniums are a good example of a succulent that will go into summer dormancy if the temperatures are too high, especially in a greenhouse, and they enjoy being out of doors in the UK climate. For this reason, it is important especially during periods of bright sunny hot weather to provide cooler conditions in the greenhouse or move plants out of doors. Perhaps the biggest decision about watering comes from when to put them into dormancy and when to bring them out of dormancy as succulents are very fickle and if too wet will quickly rot during their period of dormancy. The biggest tip to keep in succulents alive is to water them only when the soil is dry. During periods of natural dormancy, some plants can look extremely dehydrated and shrivelled, and I would recommend avoiding watering during their normal dormant period. However, if plants are being grown in conditions above 10° C they will require far more water than a plant being grown at just half that temperature. Overriding this is the fact that if they are in their dormant season it is far better not to water at all. Winter dormancy As we have explained, succulents that are winter dormant often grow most in spring and autumn and will require more water during these periods than at the height of summer. Once temperatures drop below 5° C, you will notice growth slows dramatically, and you need to limit the amount of water these plants receive as they will easily rot. This is one reason a top dressing of grit is applied to keep the lower foliage away from the damp compost. Summer dormant succulents prefer cooler temperatures for active growing. Here again their active periods are typically spring and autumn and this group of succulents typically dislike high summer temperatures, temperatures above us 16 Celsius at night can be detrimental if plants are too wet. The result typically leads to rots of the root system, and plants in this instance are best repotted into the smallest possible pots containing a dry compost and kept in the shade in the hope they will recover. I prefer not to remove any foliage while that particular succulent is dormant, as this may lead to a wound that allows fungal infections to attack the plant. During the active growing period, many subjects can be watered overhead, and I even resort to a fine rose on the end of a hosepipe. However, I would never water from above when plants are going into coming out of dormancy. In this instance I always water into pot saucers, making sure that non-is allowed to remain in the saucer after a few minutes. You could place plants in shallow trays containing five CM of water for just a few minutes before placing them back in a well drained position such as a slatted or gravel filled bench. This is especially important with certain sections of some succulent plant families, like the Agavoides section of Echeveria. Air movement and good ventilation must also be factored into the decision of whether to water are not as plants go into and come out of dormancy. Aluminium greenhouses, while being relatively maintenance free will during autumn and early winter often have the effect of excessive condensation on the inside of the glass and this can be a most serious problem for winter dormant succulents. Regularly opening doors to allow the condensation to disperse and the use of fans to move the air to prevent fungal infection breaking out on damp leaf surfaces is also to be recommended. The timing of watering is also crucial, I recommend that all winter watering along with plants coming in or coming out of dormancy are watered in a morning. This allows time for excessive moisture to drain away and coupled with good ventilation this should minimize the risk of rots. Little feeding is needed when plants are coming in and out of dormancy, but proprietary cacti food or tomato fertilizer at half strength can be used on most species during the active growing seasons. I also try to carry out potting once a specie has come out of dormancy, I dislike potting as dormancy of a species approaches and in all cases try new shallow small pots containing a very well drained succulent mix. In my case, most of my subjects thrive in a John in his number one compost with an additional 25 to 33% by volume grit and a 13 to 25% by volume of clay granular cat litter. This seems to give the best drainage, while the clay granules may help retain some of the nutrient. One of My five greenhouses My 10ft (3.05 metres) x 8ft (2.44 m) Robinson Royale second hand greenhouse with some of my succulent collection, note the two mobile tray trollies in the pathway. These maximize the number of plants housed in the winter but are easily wheeled out of doors for the summer. This provides cooler conditions for some species that if left in the greenhouse may go summer dormant due to higher temperatures. Summer Dormant Succulent Species (Winter Growers) Some succulents actually grow and thrive under cooler temperatures more typical of our average winters. While some succulents will tolerate and survive temperatures below freezing without major problems, as a general guide the lower the temperature the less water the plants in the following list will require. For example, Aeoniums being overwintered in a home with central heating will require far more water than those being kept alive in a frost free greenhouse. In both cases, it is important to appreciate that good quality bright light is essential to maintaining healthy, sturdy plants. Adromischus Aeonium Aloe Anacampseros Cotyledon Crassula Dudleya Gasteria Graptopetalum Graptoveria Haworthia Kalanchoe Pachyphytum Pachyveria Peperomia Portulacaria Sansevieria Sedeveria Sedum (non-cold hardy varieties) Senecio Winter Dormant Succulent Species (Summer Growers) These are just a few examples of the more popular succulents pieces that enjoy warm summer temperatures, but usually go dormant from late October until mid-February. Like fuchsias, it is very important to remember that when succulents go dormant, it is more a practice of gradually slowing down and reducing the amount of water given to lead them into unnatural dormancy. This will also affect the quality of and timing of blooming. Adenium Aloinopsis Agave Ceropegia Echeveria Echinocactus Euphorbia Ferocactus Mammillaria Mangave Notocactus OpuntiaParapodium Pedilanthus Rhipsalis Schlumbergera Sedum (Cold hardy varieties) Sempervivum Stapelianthus Tillandsia Titanopsis This factsheet will be further expanded as time permits, please come back to check.