The challenges of gardening in the high desert of Arizona's Rim country can try the patience of even the most ardent and experienced gardener.
Conditions include hot, dry summer days, with nighttime temperatures dropping 30 degrees; winters without adequate moisture; warm early spring days that bring fruit blossoms, and late killing frosts that drop all the fruit; gravelly decomposed granite that water drains through too quickly; and clay soils that don't drain at all. Confusion reigns as to when to plant and what to plant, and how to get it to grow, but once the challenges are met, a high level of success can be expected.
Many new residents of the Rim country come from places with much different climates and growing conditions. Plants that thrive in areas with high levels of precipitation, high humidity and acidic soils will not do well in most of the arid Southwest. Soils warm more quickly due to the altitude and latitude, and even with the danger of late spring frosts, normally the growing season starts a little earlier here than in other parts of the country.
Vegetable gardeners face special challenges, but the rewards are greatest for those who accept the rigors of climate and soil conditions. With the growing season quickly approaching, it's time now to plan and prepare for harvesting homegrown fruits and vegetables later in the year. Vegetables require about 6 to 8 hours of sunlight per day, although some types will tolerate partial shade.
Ground preparation is the first step and extremely important. The University of Arizona extension service has an online Master Gardener manual that will guide the novice and expert alike to a successful vegetable garden. www.ag.arizona.edu/ pubs/garden/mg/index.html. This site has a planting guide for various elevations around the state.
Some experts recommend double digging to a depth of 12 to 18 inches, working in about 4 inches of compost. Ensuring good drainage is necessary for deep root growth, and deep tilling will break up any clay deposits beneath the surface. Sand can be added to clay soils to loosen them up, and additional organic material may be necessary to help hold moisture in very sandy or gravelly soils.
While preparing the planting bed, testing the soil for its pH and other nutritional qualities will prevent disappointment later. Test kits are available at nurseries for a nominal fee. A soil thermometer is also useful for tracking soil temperatures. Many vegetables will germinate at 55-65 degrees, temperatures that can occur as early as mid-April in many Rim country microclimates. Keeping a roll of row cover on hand will be helpful to fend off fickle late spring frosts.
The vegetables that grow the most successfully are the ones adapted to hot, dry growing conditions, originating in southern climates globally. Not only will these foods thrive in our sunny, dry climate, they take the least amount of water, and are more pest resistant than foods better adapted to cooler places.
Think Southwest menus and Mediterranean cuisine, and a long list of plants will come to mind. Beans, squash, tomatoes, peppers, onions, garlic, cucumbers, and most herbs will readily fill the garden, table and pantry.
Seeds of Change, 1-888-762-7333 or http://www.seedsofchange.com based in Santa Fe, NM stocks a good selection of heirloom vegetable seed varieties that are well suited to Western gardens.
Closer to home is Native Seed Search in Tucson, www.nativeseeds.org. Have a look at their website, which features native and heirloom seeds.
Gardeners can get a head start by sowing seeds in planting trays indoors, and setting plants out later in the spring.
Good bedding plants are available from local nurseries, and if consumers are interested in certain varieties, they sometimes are available by special order. When preparing the garden bed for planting, consider planting in blocks with stepping-stones in-between, so plants can be reached easily without walking in the garden.
In dry climates, a water conserving method of planting is to plant in the furrow, which will gather water naturally when rains come. Loosely applied straw or pine needle mulch placed over the seedbed will allow the penetration of sunlight and water, but will keep the soil a more constant temperature, and shade the seedlings.
Install a drip irrigation system or a soaker hose layout for getting water to the garden. The use of sprinklers is prohibited by the town of Payson water conservation ordinance, and are less efficient than ground emitters. Drip tubing which is about 1/2-inch in diameter and laser drilled will distribute water evenly and slowly. It is flexible and can follow the contours of the garden. Although the soil must be kept moist for germination, once the seedlings appear, allow the surface of the soil to dry out between waterings. Once the plants are established, water according to requirements for the individual variety.
Grouping plants with similar water needs will make laying out the drip system more efficient. Watering maturing vegetable plants very slowly over a long period of time is much more beneficial to plants than frequent, short watering times.
Apply 2 to 3 inches of mulch around plants, taking care to keep the immediate area around the stem clear. Mulch is attractive, covers the mechanics of the drip system, helps discourage weeds and holds in moisture.
In addition to the seasonal vegetable garden, many perennial herbs, such as yarrow, sage, thyme, oregano, lavender and rosemary, thrive in the high desert. They form woody stems and though dormant in winter, dependably return with foliage and flowers each spring, and can be incorporated into a flowerbed, or planted among other ornamentals. They are drought-resistant once established, and will thrive with deep soakings about every 10 days or so. Annual herbs, such as basil, dill, and cilantro must be planted from seed each year, and are good candidates for planting between vegetable plants.
All herbs prefer a sunny location, at least during the morning and early afternoon hours. Good drainage is necessary, so cut through the caliche layer and mix in plenty of organic matter if soil is heavy. Seeds may be planted in early April; and annual herbs such as dill, chives and basil can be planted every two weeks to allow for dieback in the event of cold, late spring weather. Perennial herbs can be put in the ground this month to get a head start on summer growth, but watch nighttime temperatures and protect with row-cover material if heavy frosts are predicted.
If the ground is not too wet to be worked, bare root roses, grapes, raspberries, blackberries, fruit and shade trees can be planted as soon as they are available at the nursery.
Planting bare rootstock as early as possible gives the plant a chance to rest and establish roots before the spring growth spurt begins.
If a water harvesting system can be designed to channel run off to fruits and berries, these productive plants will offer ornamental value, shade and produce, as well as helping to conserve water.
Planting deciduous fruit trees on the South and West sides of the home will add the advantage of cool shade in the summer.
Contact local nurseries for additional information and services.
The town of Payson has information on water conservation, and the information kiosk at the low water-use demonstration garden at Gila Community College has brochures and fliers.
The High Country Xeriscape Council of Arizona maintains a website at www.xeriscapeaz.org which carries lots of information on composting, water harvesting, and tips for gardening in the Rim country.