Succulents have thick, fleshy leaves and stems that store moisture and nutrients. This ability allows the plants to thrive in dry conditions. Potted succulents often require less watering and fertilizer than other houseplants, but they require nutrients out of the soil, so they need periodic feeding. Too much fertilizer, especially high-nitrogen blends, increase leaf and root rot problems. It is vital to use the right blend and avoid overfeeding to keep the succulents healthy.
Dissolve a low-balanced soluble fertilizer, such as an 8-8-8 or 10-10-10 formula, in 1 gallon (3.8 l) of water. Use half the amount recommended on the package for most succulents. For example, use half tablespoon 10-10-10 fertilizer if the label recommends using one tablespoon per gallon of water. Dilute to one-quarter strength for tropical succulents that require more frequent watering, such as a Christmas Cactus.
Water succulents with the half-strength solution until the excess moisture begins to drain from the pot bottom. A gallon (3.8 l) of fertilizer solution may be enough to feed several plants, depending on size. Apply the fertilizer in spring as new growth begins and again in late summer or early fall. Do not fertilize when the succulents are semi-dormant in winter.
Water tropical succulents weekly with the quarter-strength solution during the plant's active growing season. Some tropical species actively grow in summer, while others are winter growers. Stop the fertilizer applications when plant growth naturally slows.
Apply fertilizer when the soil in the top inch (2.5 cm) of the pot has dried completely. Postpone a weekly application if the soil is still moist so that the soil can dry.
You can substitute the quarter-strength fertilizer for most succulents if the soil is drying rapidly in the pot and necessitating more frequent watering. Frequent irrigation flushes the nutrients from the pot before the plant can access them.
Outdoor succulents usually do not require fertilizer because they can access the nutrient store in the soil. If they do need feeding, apply half the recommended amount of a balanced slow-release fertilizer in spring.