Fertilizer for Flowering Cactus

Fertilizer Analysis

• The analysis of a fertilizer indicates how much of the three key nutrients--nitrogen, phosphorus and potassium--the fertilizer contains. Flowering cactus require more phosphorus, which aids flowering, than they do nitrogen. Too much nitrogen produces excess succulent leaf growth on the cactus and makes it more prone to insect and disease problems. A 5-10-10 fertilizer contains 5 percent nitrogen and 10 percent quantities of both phosphorus and potassium. This and other low-nitrogen fertilizers are preferred for most cactus plants.

Types of Fertilizer

• Fertilizer comes as either a water-soluble or a time-release fertilizer. Time-release fertilizer, sometimes called granular fertilizer, does not require frequent applications like soluble types do. These fertilizers release nutrients slowly over a period of several months. They can be more difficult to incorporate into the soil of a small cactus pot, though. Most fertilizers formulated for houseplants such as cacti come in a soluble form. These require more frequent applications but they are simpler to apply.

Application and Timing

• Flowering cactus only need fertilizing when they are actively growing. While cactus are evergreen, they do enter a semi-dormant state. Most holiday cacti go dormant in the summer months. Begin fertilizing once the cactus begins producing flower buds. Apply a soluble fertilizer once every two to four weeks at the rate recommended on the package. Continue to fertilize until the cactus quits putting on new growth, usually in spring, except for Easter cactus varieties, which go semi-dormant in fall. If you choose a slow-release fertilizer, apply it once a year when flowering begins.