Excess fertilizer applied to any plant, succulent or not, can cause roots or leaves to burn. The tips of leaves that turn brown are a sign you may be feeding too strong a fertilizer or that you are feeding the plant too often. Succulents should be fed a good house plant fertilizer given at ¼ strength recommended on the manufacturer’s label. Succulents do not appreciate high does of nitrogen that can make the plants grow flabby and weak. One-fourth strength of a 20-20-20 house plant fertilizer is okay. Those numbers represent, in order: nitrogen, phosphorous and potassium.
- Nitrogen enriches the green coloring of plants and promotes stem growth.
- Phosphorous encourages flowering and root growth.
- Potassium strengthens stems and help plants to resist disease.
Try to select a fertilizer that contains trace elements, also sometimes referred to as micronutrients. Never fertilize during winter months. Fertilizing a sickly plant will only help to kill it. During the growing season, a monthly feeding is enough. Using a little good old garden compost in your mix is far superior to chemical fertilizers because chemical fertilizers do not do the soil any good long term. Compost, on the other hand, conditions the soil as time goes on. If you use compost in your mix, chemical fertilizers are not necessary, providing you repot into fresh mix periodically. Most plants should be repotted every couple of years anyway. Those too big to repot should have the top couple of inches (or more) of soil removed and new mix added.
(Information taken from Marina’s very old url in Wayback, originally at http://vvv.com/~amdigest/thisthat.htm)