Cactus and Succulent Care:

While succulents are native to arid regions and generally thrive in poor soils, it does not mean one should not water them or provide nutrients. How often should you water? There is no answer that is universally correct. There is a direct relationship between water, light, temperature, soil conditions and humidity. The higher the light level and temperature and the less humid the more often watering is required.

Most cactus and succulents have an active period about 1/3 of the year. During this active period watering can be frequent and fertilizer applied. The most active time for most cacti is during the spring and early parts of summer. As this period passes, it is best to reduce the frequency of watering as winter approaches. They require very little water during the cold months. A good watering once a week in hot weather and once a month in the dormant period is a good point to start as you learn your plants needs. Another approach is when the soil is completely dry, water thoroughly then let dry. If in doubt, don’t water.

Too much fertilizer can be worse than none at all. Use a low nitrogen fertilizer at about ½ to ¼ the recommended rate.

Other succulents are more complicated. Many do not adjust their active periods because they are growing in a different hemisphere than their native land. You need to learn the winter growers from the spring to summer growers and treat accordingly.

What is the best soil for cactus and other succulents? Most commercial potting soils are too rich in fresh organic matter for these plants. The most important factor in choosing a planting medium is that it allows food, water and air to get to the roots and is porous enough to let water drain through. Many growers use a mix of a low peat planter mix and pumice (50/50). Sand, small pebbles and vermiculite are ingredients added by many successful growers and hobbyists. Experiment with different combinations to discover the right combination for your conditions.

What size pot should I use?  In many cases it is best to under pot rather than over pot, when potting slower growing or rot prone species.  The more substrate in the pot, the more water that is going to be stored in the pot; larger pots take longer to dry out which can lead to potential problems with rot.  Cactus like Cereus, Trichocereus, Stenocereus, Myrtillocactus, Opuntia are usually suitable for larger pots since they are not as sensitive. Your substrate mix and local climate play an important role in this as well.

A top dressing of crushed granite or pea gravel looks good and has benefits as well. It keeps the topsoil from drying out faster than the rest of the soil in the pot, keeps the base of the plant dry and assists in the even distribution of water through the soil.

Direct sun and light are not the same! Succulent plants need light but they grow better if they don't cook in the midday sun. In the wild you will find young plants tucked under a bush, tree or something else that provides filtered light. If new growth on your plant is pale green and elongated, it needs more light. If the side of your plant facing the light source is yellow, tan, red or indented, it is getting too much light.

Succulents do not like stagnant air. Provide good air circulation for your plants.

An excellent source of information is the Cacti etc mailing list. Hobbyists and professional growers from around the world subscribe to the mailing list. Many are growing and enjoying these plants in conditions just like yours, a great place to learn and share experiences. Have a specific question, search the lists archive.

There are many excellent books on the market that can help with culture and identification of these plants.

Interesting reading on cactus, succulents and the North American Southwest: