10 tips for container gardening in the desert

Despite all of these difficulties, containers can be a good option in a number of cases.

If you live in an apartment or townhouse, they may be your only option for growing plants. If you want to grow some non-native plants, containers may be your best bet, particularly for those plants that like acidic soils. Containers are also movable, which gives you the option of planting things that may need to go inside for the winter or that may need to be moved into the shade in the summer. So what’s a gardener to do? Here are some tips:

• Use large containers, at least 24x24 inches wide and deep, to minimize watering needs.
• Feed regularly with natural fertilizers to compensate for the lack of nutrients in the pot. Avoid synthetic fertilizers; they injure or kill natural microbes in the soil and can make nutritional deficiencies and imbalances worse. You wouldn’t try to survive on a diet of vitamin pills, so give your plants the nutrients they need with compost or an organic natural fertilizer like chicken manure.
• Drainage is important — don’t block holes when placing the plant in the pot, and don’t place it in a dish. If you overwater and the dish fills up, your plant has no drainage. This is particularly problematic for drought-adapted plants. Do not put gravel, rocks, pebbles, or any other materials at the bottom of the container. Contrary to popular belief, this actually worsens drainage and reduces the amount of soil available to your plants. Do not use native soil — it will not drain properly. Use potting soil for regular plants and cactus potting soil for cacti and other succulents.
• Check moisture regularly — smaller pots, particularly in full sun, will likely need to be watered twice daily in the height of summer. You may need to move your containers based on the sun and season.
• Plants can root into the ground through the pot’s drainage holes so place the pot on something hard or elevate it on bricks or something similar if you don’t want this to happen.
• Even cacti need shade cloth in full sun; 40% is ideal. Put a mark on the pot to indicate the side of the cactus that is facing south and don’t change the orientation.
• Add woodchips, bark, or other organic mulch to the top of the soil in your pots to slow down water loss and to shade and cool the soil.
• Different container materials have their pros and cons. Clay pots allow your plants to “breathe” but also dry out quickly in our hot summers. Plastic pots can be inexpensive and attractive, but may not last long in the sun, depending on the material. Steel and other metal gets hot in the sun, but is a good choice for very large containers. If you’re looking to save money, repurpose other items as planting containers. Even things like old sinks and toilets (yes, toilets!) make good containers, and can be purchased inexpensively at building supply recyclers such as Gerson’s and HabiStore. Don’t use cloth bag containers. These don’t do well in our climate as it is too hot and dry. And whatever container you use, make sure it has drainage holes.
• Your plants need room to grow. Don’t stress them additionally by crowding several into a too-small container. You can plant a nice grouping if you use a larger container. The rule of thumb for nice container designs is to plant a thriller, spiller, and filler: a focal showstopping plant with a plant that spills over the side and a third plant to provide a nice background. In addition, when you plant combinations into a single container, make sure you do not mix shade and sun plants.
• Consider whether you will move the container. If so, put it on a platform with casters before you put in the soil and plants.

For additional tips, check out these helpful resources:

• Container gardening in the Southwest desert; University of Arizona extension office. 
• Container gardening tips from Arizona Municipal Water Users Association.