General Care for Cacti and Other Succulents
the basic principles.
Cactus and other succulent plants are easy to grow, and are non-
Keep in mind that cacti and other succulents are remarkably diverse and widespread plants. There are tens of thousands of species, varieties, and hybrids of succulent plants; different plants may be adapted to very different climates. A few species occur well into artic regions and will tolerate temperatures to below -
As a rule, cactus and other succulents are adapted to conditions of:
1. Bright light.
2. Periodic to frequent drought
3. Warm temperatures
4. Fast draining, fertile soil.
Light provides the energy for plants to grow. Providing adequate light levels is probably the most important factor in the long term success in growing cactus and other succulents. For the most part, succulents are adapted to conditions of bright light. The majority of species grow in exposed areas, and are adapted to grow in direct sunlight to light shade. Home interiors are much dimmer than people imagine, typically providing only about 2% to 4% of the intensity of full sunlight. Most succulents should be provided with the brightest spot available to produce their best growth. A sunny window, with a southern or western exposure is best, but an eastern exposure may be adequate for some species. If the light levels are too low, it is possible to grow some species under artificial lights. I have grown a number of species (primarily Haworthias, Gasterias and a few miniature Aloes,) under fluorescent lights and LED lights with good results. If plants are to be grown under artificial lights, the lights should be held only a few inches above the plants, otherwise the light which reaches them will be too dim to produce strong growth (I have found that incandescent lights produce too much heat to be useful for plants).
In the spring, once temperatures rise to the 50s and 60s, I move the plants outdoors to benefit from the increased light levels, summer temperatures, and rain fall (I will speak more on the benefits of rainwater under the Water section). It is best to introduce these plants to increased light levels gradually, allowing the plants to acclimatize to increased levels of sunlight. I usually begin moving my plants to a shaded area outdoors on a cloudy day; after several days to a week, I move my plants to partial shade (again, moving them on a cloudy day); after a few days to a week, I move them to a spot in the full sun. Even succulents may be prone to scorching if they are immediately moved from interior spaces to full sunlight. Scorching will leave scars on stems and foliage; in time, new foliage will replace old foliage, but stem scarring is usually permanent. While this may mar the appearance of the plant, this is seldom fatal. Those species which are adapted to somewhat shaded situations (Haworthias, Gasterias Christmas Cactus and some of the miniature Aloes,) will probably grow best in light shade.
When temperatures start dipping below 50 degrees in fall, I move my plants indoors.
While many books tout the remarkable ability of some succulents to survive extreme and extended drought (some species can survive two years or more without significant rain), only a tiny minority of cactus and succulents can survive such extreme conditions. The overwhelming majority of these plants originate from regions which are seasonally dry, but will experience a short but significant rainy season. When actively growing, most succulents will require substantial amounts of water: it is best to give them ample water (enough so that excess water flows through the drainage holes of the pot), watering the plants again only after the soil has become completely dry. Succulents should never be subjected to continually moist conditions, but during their growing season it is just as important that the plants are not subjected to an extended drought. I typically water my plants once every 7 to 14 days in summer, but much less frequently in winter (when most of these plants are dormant) -
Summer is also a good time to fertilize succulents. I generally choose a fertilizer which can be dissolved in water and applied when the plants are watered -
Water quality is another important consideration in growing succulents; well water and water from many municipal sources have significant levels of dissolved salts, and mineral compounds (calcium carbonate for example). Municipal water usually has levels of chlorine and fluorine which may also be detrimental to plants. In potted plants, these minerals tend to accumulate in the soil, and may eventually build up to levels which are detrimental to their health (this accumulation of salts and minerals in the potting soil is probably the most important reason for periodically repotting plants). Most of the succulents will benefit when grown where they will receive summer rainfall. Rainfall can flush salts and harmful concentrations of minerals from the soil, which tend to accumulate when plants are exclusively watered with water from municipal water systems or wells. Summer rains can also assist in the control of certain harmful pests (spider mites for example), by washing them from the plants. In recent years, there has been some discussion of the importance of watering succulents with acidified water. Not only does the use of acidified water limit the accumulation of some dissolved minerals, it is also important in the uptake of key nutrients from the soil. Ideally, the water used in watering succulents should have a Ph in the range of 5 to 5.5 -
Most of the succulents grow best during the summer months, when there is good light, adequate moisture, and warmer temperatures: at this time, growth can be dramatic; under ideal growing conditions, some succulents can easily double or even triple in size in a single growing season -
Potting, and Potting Soil
Succulents will occasionally require repotting. Most species may only need to be repotted every 2 years or so depending upon the species and the growth rates of the plants -
I have had very good results growing Succulents in a potting medium containing a high percentage of Moo-
Most of the succulents should be given cool and dry conditions during the winter months, to keep these plants dormant. Dormant plants will usually tolerate temperatures which are quite cool, some to temperatures falling to the low 40's -
Air and Air Circulation
Often forgotten as a requirement for plants, atmospheric gases, particularly oxygen and carbon dioxide, are nevertheless vital. Deprive a plant of these gasses, and it will quickly perish. Carbon, extracted from carbon dioxide during the process of photosynthesis is a basic building block of all living things, and is a necessary component of all proteins, fats and sugars.
Conditions of perpetually high humidity may impair the health of some cactus species. Humid conditions may provide environments suitable for the proliferation of molds, fungi, and bacteria as well as any number of insects pests. It is for this reason that I do not recommend growing succulents in a closed environment such as a closed terrarium -
Good air movement can be an important factor in the health of many succulents. Moving air may help to facilitate transpiration, and may help to limit the conditions of high humidity and may prevent the proliferation of certain pathogens. If you grow your plants next to a window, consider opening the window (weather permitting) to provide good air circulation. Registers and fans can also provide good air circulation, but remember that central heating and air conditioning will quickly dry out the soil, and plants grown near registers, fans, etc., will require more frequent watering.
Every bit as important, are the gasses which are present at the roots of a cactus. A soil which includes a high quantity of relatively large particles (coarse sand, gravel, stones, etc.) allows for the diffusion of air into the soil, and just as importantly, allows for carbon dioxide to diffuse out of the soil. Waterlogged soils do not allow for a free exchange of oxygen and carbon dioxide: in waterlogged soils, concentrations of carbon dioxide may rise to lethal levels, killing the roots. The same anaerobic conditions may create an environment suitable for the proliferation of certain soil fungi which will infect dead and dying tissues, and may ultimately kill the plant. This is usually what occurs when a plant is killed by "over-
Most of the succulents are fairly disease and pest resistant, but a few pests are known to be a problem. In greenhouses and other sites where plants are grown under hot and dry conditions, spider mites can become a problem. Spider mites are tiny -
Mealy bugs and scale insects are pests which are difficult to eradicate once they have become a nuisance. Mealy bugs are slightly larger than the size of an aphid, and are typically of a grey to white coloration. Many individuals produce a waxy coating which may give them a whitish appearance, and some may produce such an abundance of fluffy wax that they look like tiny tufts of cotton. Mealy bugs usually occur in groups in the tight recesses of succulents, and are not always readily apparent -
Scale insects may look like tiny grey or brownish blisters. I tend to think of scale as an insect take on the design of the limpet; the insect hides beneath a low conical "shell", and do not look much like an insect at all. Control of scale is similar to the control of mealy bugs, but because these pests may be a bit more cryptic than mealy bugs, they may be present in huge numbers before their presence is even detected. In all cases, large infestations of any of these pests may require stronger measures -
As a rule, healthy plants which are actively growing tend to be fairly resistant to insect infestations, so the presence of insects may possibly indicate that the plants may be weakened due to some other cause: once the pests have been dealt with, a change in growing conditions may be indicated.
Keep in mind that these are general guidelines only: there is no single formula which will work with all succulents -
Feel free to experiment, learn what works best for you and the plants in your own collection, and realize that a few mistakes will not cause the immediate demise of your plant -