If you think that it must be impossible to grow much of anything in the hot, dry climate of the desert, never mind fruits or vegetables, you might have a surprise coming. Arizona, located in the Sonoran desert, grows a number of crops commercially including cotton, citrus, lettuce and cantaloupe. Home gardeners have a wide selection of fruits and vegetables to grow in their yards.
Prepare the Soil
Dig to a depth of 24 inches for a new garden. Desert soils often have a layer of caliche (calcium carbonate) below the surface. This substance is very hard and prevents proper drainage. It also acts as a barrier for plant roots. Use a pickaxe to punch through the caliche.
Add a 2-inch layer of gypsum to counteract the alkalinity of desert soils. The gypsum prevents the formation of hard clumps in the soil as well. The water in desert areas tends to have high levels of minerals, which adds to the alkalinity of the soil.
Spread a 4-inch layer of compost. Since the desert is dry, many of the plants, like cacti, have no leaves. Others, like ironwood trees and palo verde trees, have very small leaves. As a result, there is little organic matter added to the soil by native plants.
Install an irrigation system. This is the best solution to make sure plants get the right amount of water at the proper intervals. The water gets right to the fruits' and vegetables' roots and isn't wasted through evaporation as it would be with a sprinkler.
Water consistently. When the temperature is over 100 degrees F--and that happens nearly every day through the months of June, July and August--vegetables need water every other day. Irregular watering causes problems such as tomatoes cracking or developing black spots.
Deep water once a month to flush the minerals and salts from the soil that accumulate due to watering.
Fruits and Vegetables
Choose varieties that do well in the desert. Check with members of the local Master Gardeners or university agricultural extension. High temperatures and low humidity, typical desert summer weather, affects fruit setting on tomatoes, peppers and squash. Some types do better than others.
Plant warm-season fruits and vegetables like corn, watermelon, and tomatoes as early as possible in the spring. They will have produced a crop by the time the heat hits.
Shade the plants during the hot afternoon sun. Locate the garden next to a wall or use shade cloth. In an emergency when temperatures are over 112 to 115 degrees F, throw white sheets over the plants and wet down the sheets. The evaporation will cool the plants enough that they will most likely survive.
Plant two cool-season crops like lettuces, peas, broccoli and leafy greens. Plant the first crop in December or January and the second crop in August.