Gardening in the low desert of Phoenix, Arizona, is a bit different than gardening in much of the United States. With its extreme climate and summer temperatures regularly surpassing 100 degrees F., growing vegetables can be tricky. Plan on sowing your garden in winter and spring as opposed to the usual spring and summer seasons. Summer in Phoenix is too hard on vegetables with extremely hot days causing vegetables to bolt or not set fruit.
Test your garden soil. According to the Arizona Cooperative Extension, Arizona soil is generally lacking in phosphate and nitrogen. A soil pH test, either done with an at-home kit or through your local Extension Office, will recommend soil amendments. If you have heavy clay, spread a 6-inch layer of compost or peat moss and add the amendments into the top 12 inches of soil.
Choose your vegetables. Cool-season vegetables such as beets, carrots, peas, spinach and turnips can be planted in late summer or late winter. Warm-season vegetables such as tomatoes, sweet corn, cucumbers, melons, peppers and beans can be planted in late winter or early spring. When selecting a warm-weather variety, look for plants that harvest quickly so the crop is finished before the hottest of Phoenix's summer days arrive.
Water your plants several hours before placing them in the soil. Set out transplants on a shady day, in late afternoon or early evening, to prevent wilting, the Extension recommends. Even in the cooler months, Phoenix's intense sunlight is hard on newly planted vegetables.
Place newspaper or cardboard on the south side of your plants for the first few days after transplanting. You also can cover them with baskets or flower pots to protect the tender transplants from wind and sun until they are established.
Water once a day for the first week after transplanting, unless there is rain. Slowly reduce your watering to every third day. In the heat of late spring and summer, when Phoenix rainfall is minimal, you may have to return to daily waterings. A soaker hose, which slowly seeps water directly into the soil, reduces water waste and evaporation.
Cover your garden with 4 to 6 inches of mulch to aid moisture retention and reduce weeds. Phoenix gardeners may want to avoid plastic mulch, which raises soil temperatures substantially.