The arid landscape of Arizona may appear an inhospitable environment for vegetable, herb and flower gardens. It is possible, though, to coax food and foliage from the dense soil, and the duo growing seasons are owed to the extended months of sunshine and mild winters. Planting in Arizona, be it vegetables, herbs, flowers, trees or grass, requires a different approach to soil management and planting schedules than in other regions of the United States.
The soil in Arizona is heavy, clay-like soil that is rich in minerals but low in organic matter. The scrub and cacti plant life common to Arizona survive on little water and shallow root systems. Limited organic matter, such as grasses and vegetable matter, is available for natural composting. Hence, the soil is heavy, rocky, compacted clay.
Soil amendment is a necessary part of gardening in Arizona. For vegetable gardens, you may need to add as much as 50 percent compost to freshly turned dirt to achieve a soil healthy enough to sustain plants other than cacti and thistle.
Adding compost and other amendments, such as gypsum, allows plants to take advantage of the naturally occurring nutrients found in the soil, such as calcium, magnesium and iron. The amendments not only add additional nutrients to the soil, they make the soil friable. Friable soil is less dense and has more air pockets, which allows roots to penetrate and take up soil and nutrients.
Amending your soil will make for a more hospitable environment for your plants, but only if you plant at the right time. The growing seasons for Arizona are from February to May or early June and from September to late December or, if you're lucky, early January.
The growing seasons in Arizona differ from the majority of other regions in the United States. In mid-summer, when other gardeners are beginning to gather their bounties, you, as a resident of Arizona, are harvesting the last of your vegetables, deadheading your flowers and otherwise "summerizing" your garden. Cut back plants once they stop producing and put the material into your compost. Allow your garden beds to rest in the summer, placing a layer of composting mulch on the soil surface and watering lightly once a week.
Plant tomatoes, cucumbers, peppers and squash in early to mid-February, selecting varieties that are ready to harvest by May. In June, July and August, temperatures rise above 100 degrees and the plants will cease to produce.
Cool season crops are planted in September and October. These include broccoli, winter squash and root vegetables such as carrots.
A variety of perennial herbs will survive the hot summers of Arizona, keeping a bit of green in your garden. Plant rosemary and thyme, both perennials, in your garden. Mints are prolific in spite of the heat, as are basil and oregano, though you may need to provide artificial shade for them during July and August.