With proper care these plants can thrive!
Succulents can be grown either inside or outside but, like other plants, they need plenty of light. Most require either filtered sun most of the day or 1 to 2 hours of direct sun each day. Many will survive quite well in full sun, but in summer you will need to introduce them in stages: 1 to 2 hours the first week, 3 to 4 hours the next week, then all day. Some species just require good light, for example: Aloe, Scilla, Gasteria, and Haworthia. For outdoor plantings, choose a location that receives year round sun and is not in a low spot or a frost pocket.
Any good cactus and succulent mix, prepared and bagged, and available in many nurseries and garden shops can be used for your cacti and succulents. Or, you can use a high quality planter mix or humus. For this, add two parts perlite or pumice and one part washed building sand. Adjust the ratios according to your growing conditions, climate and the plant in question. To grow outdoors, amend the soil with sand or create raised beds to allow for well-drained soil.
With succulent plants you must be careful to make sure the plant needs water. Feel the soil at least one inch down and if the soil is dry it is time to water the plant. If potted, let the water thoroughly drain through the roots and out the bottom, making sure the entire pot of soil is saturated. Drain thoroughly; never let plants sit in water. Use a soil mix that drains well and allows some drying out between waterings. Top dressings, such as small pebbles or coarse gravel, offer quicker water penetration, slower water evaporation, elimination of a crust on the top of the soil, and a neat, attractive appearance. When plants are vigorously growing and blooming, they will need more water. During their non-growing or resting stage, usually in cold winter weather, they will need very little water.
Most succulents and cacti benefit from the addition of diluted liquid fertilizer added to the water every second or third watering during their growing season. Any standard houseplant fertilizer with balanced amounts of nitrogen, phosphorous and potassium (20-20-20) can be used. It is also convenient to use one of the slow release granular fertilizers. To induce bloom and improve flower size, a fertilizer with low nitrogen and high phosphorous content can be used. Always dilute more than the stated instructions advise, as recommended dosage is too strong for these plants. If your plants are growing too lushly and/or are losing their characteristic shape, this may be the result of over-fertilizing. As a rule, it is safer to under-fertilize than over-fertilize.
Pests and Diseases
Many succulents are prone to mealy bug (appearing as small white fluffy balls on the leaves towards the inside of the plant) and aphids (tiny black insects, often on the flowers). If there are only small numbers to be dealt with, dabbing them with a little denatured alcohol will kill them. For large or widespread infestations, use regular applications of insecticidal sprays after washing off as many as possible with a high pressure water jet from a sprayer. Snails can be problematic for outside plants; control by hand-picking or treating with a snail and slug bait.
Over-watering is probably the single most common cause of failure of succulent plants to thrive. The plant may appear to do well at first, its leaves plump up and new growth produced. However, the roots may be suffering in wet soil and begin to rot unseen. The plant still looks well as the few remaining roots are able to take up sufficient of the plentiful water. As the roots continue to die in the stagnant soil, a point is reached at which they are unable to supply sufficient water and the plant appears to be suffering from lack of water. If more water is supplied, the situation gets worse and the rot may spread upwards into the basal stems or plant body. Eventually the plant body is observed to be soft and discolored, perhaps yellow or grayish, by which time it is usually too late to save it. The moral is that if a plant appears to be failing to take up water, examine the condition of the roots before supplying more water.
Pruning and Maintenance
Succulents rarely need pruning unless they are outgrowing their space or they have been growing in a low light situation.
In the winter time, keep your cacti and succulents in temperatures above freezing. They will go dormant and manage just fine in night time temperatures of 35° to 40°F. More tropical succulents like Euphorbia and Epiphyllum prefer warmer night time temperatures of between 50° and 60°F. However, if you harden them off by watering less in the fall, they will tolerate temperatures in the mid-thirties. Other less tropical succulents, like many cacti, Sempervivum, Sedum and Agave, can tolerate lower night time temperatures into the mid-twenties (or less) when they have been gradually acclimated to cold weather. In the summer, protect your cacti and succulents from extreme heat. If temperatures reach over 100°F, be sure to shade your plants and provide air circulation. When it is both humid and hot, it is particularly important to have good air circulation and careful watering to avoid fungus and rot problems.
For handling and transplanting smaller plants, thin rubber gloves can be used to protect the fingers. Tongs that have been wrapped with tape or other material to prevent damage to the plant also work well. Larger plants can be handled with a short section of hose wrapped around the plant, or a sling made from a rolled newspaper can be used.
For more information on succulents, see the website for the Cactus and Succulent Society of America at www.cssainc.org.