The Trick to Keeping a Cactus Alive

Good Soil

• Cactus plants require well-drained soil. Desert varieties grow best in sandy soil that has minimal organic matter content. The flowering tropical varieties, such as the holiday cacti, require soil that contains more organic matter and retains more moisture. Use a cactus potting soil mixture for either type of cactus or create your own. Combining equal parts sand and potting soil works well for desert varieties, or mix two parts soil to one part sand for the tropical types.

Proper Watering

• Improper watering is one of the primary causes of cactus decline in the home, so the trick to keeping the plant alive is to supply enough water without overwatering it. Feel the soil before you irrigate. Only water desert types when the soil nearly dries out completely, then thoroughly water. Tropical cacti grow best in soil that remains slightly moist and doesn't dry out completely. Never allow the pot to sit in standing water. Empty the drip tray under the pot after watering so the moisture isn't reabsorbed into the soil.

Light and Temperature

• Desert cacti require warm temperatures and plenty of direct sunlight for best growth. The plants grow poorly and begin to drop needles in low light conditions. A location near a warm, sunny window works well, or you can set the pot outdoors in the summer. Tropical cacti perform best with bright but indirect sunlight, as too much direct sunlight can cause the flowers to drop prematurely. They also tolerate cooler temperatures, as low as 65 degrees Fahrenheit. Neither cactus survives freezing temperatures and outdoor plants must be brought indoors before frost.

Nutritive Needs

• Fertilization varies depending on the cactus type. Desert varieties require minimal nutrition to grow well. Too much fertilizer can cause the plant to decline in health or die. Use a low-nitrogen fertilizer for desert types. Apply the fertilizer every two to three months using only half the rate recommended on the application instructions. Tropical cactus plants have slightly higher nutritive needs. Feed these monthly during the spring and summer using the diluted fertilizer solution.