HORTICULTURAL TIPS FOR PLANTING CACTI
When planting cacti in the ground, the most important consideration is the hole into which you put the plant. Minimally, the hole should be a foot deep and a foot wide. Within reason, the bigger the hole the better. In effect, you are creating a volume of disturbed soil in the earth for the plant. Desert soils are hard. Breaking up the soil facilitates root exploration and water infiltration and helps the plant establish itself in the shortest possible time. It also leads to faster growth rates and more profuse flowering.
Unless you have hard caliche, you can use the soil from the hold to plant in. If you have caliche, discard it and get some topsoil or potting soil. Add 30 to 50 percent coarse sand, including the sandy mix from the pot. The sand is very important. It gives the soil high water infiltration capability and aeration. So when it rains, or when you trickle irrigate, the hole acts as a sink for water and the soil becomes far more charged with water than the surrounding undisturbed hard soil which has a low infiltration rate. Sand is available at the right price in your local wash. Mix the sand and the soil well, breaking up any chunks of earth. The plant can be removed from the pot by carefully setting the pot on its side on the ground and easing it out with tongs or a rolled up newspaper. When planting your plant, allow the roots to reach as far down into the hole as their length allows. This encourages deeper rooting and gives the plant access to the moisture in the lower soil layers. This will help your plant grow and prosper steadily during the hot summer months. Fill in below and around the plant with loose soil, tamping lightly once the plant is in and the soil is filled in around it. Handle the plants gently when transplanting them as minimizing the impact of the transplant on the plants, especially the roots, will also help them become established quickly. Of course, the more formidably spined ones will help you learn fairly quickly how to handle them. As an attractive final touch, spread some gravel or small stones on the ground about a foot or two wide around your plant. This gravel mulch will help keep the plant cleaner, as well as help the soil retain moisture by staying cooler. From the design standpoint, the stones can help define the area of your planting, creating an appealing island of cacti. A gnarled piece of desert wood with a few select colorful rocks finishes the job nicely.
Although these plants will do acceptably well on just the rainfall in this area, an occasional watering during the growing season from roughly March to October will help them grow significantly faster. Water infrequently, but thoroughly. Soaking the soil down deep will help keep the plants well hydrated and growing actively during the hot summer months. When you water cacti in the ground, you’re not really watering the plant, you’re charging the soil. The plant will absorb water from the soil slowly and continually as the weeks pass. The best way to water is to trickle irrigate at the base of the plant for at least several hours. Overnight is a convenient method. Trickle at a rate that wets an area no larger than two feet around the plant. Avoid spraying water all over the
place as this will germinate all the weed seeds in the upper soil layer. There is no particular watering schedule. In general, beginning when the weather warms up in the spring and carrying through to when it cools off in the fall, a plant in the ground can be watered about once a month. Plants in full sun positions need more water than ones in shadier locations. Plants in containers also need more water than plants in the ground. Once these plants are in the ground and have a chance to root out, which takes several months to, in some cases, an entire growing season, the roots explore a far greater volume of soil than a plant in a pot. The best strategy is to learn to interpret the appearance of the plant so as to understand its water status. A plant which is plump and robust is well hydrated and doesn’t need to be watered. However, a plant which has shrunken in size or one in which the ribs are becoming increasingly pronounced would appreciate some water. There is really no substitute for periodically examining the plants and learning to “read” them like this. It’s quite simple once you’ve seen it a few times. Understanding the cacti in this way will also enrich your appreciation of these fascinating plants. You may also use drip irrigation as long as you water infrequently but thoroughly.
If you wish, you may occasionally apply some fertilizer to the plants. Use a half-strength solution of any general houseplant fertilizer. Apply several gallons, adding it slowly to the soil at the base of the plant. Any fertilizer is fine in moderation. While fertilizing will enhance the growth of cacti, it is certainly an optional consideration. Once planted in the ground and having taken hold after a season, these plants will do quite well without you.
Be sure to leave sufficient space between the plants. Plant the smaller cacti no closer than a foot or so from one another. The larger specimens should be no closer than about 2 or 3 feet from any other cactus, especially when you consider that some of the larger ones become quite sizeable.
WE DO NOT SELL WILD COLLECTED PLANTS.
Prepared by Jon R. Weeks, Ph.D.