The high desert presents vegetable gardeners with many challenges, including high winds, fluctuating temperatures, poor soil and periods of prolonged drought. The growing season is as short as 90 days in some areas, and the weather is fickle, often dumping 1 foot of snow onto a newly planted garden in May, or freezing a long-awaited tomato crop in August. Soils are typically alkaline, and poorly drained, with high clay content. Low humidity and long periods of drought can stress garden plants. The good news is that with proper planning and preparation, you can enjoy the sweet taste of success in your high desert garden.
Dig a 1-foot deep hole in your garden soil with a shovel and fill it to the top with water. Observe how long it takes for the water to completely drain from the hole. Improve the soil's drainage if there is still water in the hole after one hour. Add up to one part fine gravel (not sand), and one part well-rotted organic compost to one part native soil, so that water will drain from a 1-foot hole in 10 minutes or less. Break up underlying layers of caliche, or hard pan clay, with a pick axe if necessary, to allow drainage.
Purchase an inexpensive pH test kit from your garden center or hardware store and analyze your garden soil. The most common type of pH test kit includes a vial, a special powder and a color chart. Place a bit of soil into the vial and add powder and water (follow the directions for specific dosages). Mix them up and compare the color of the water to the chart to read your pH level. Most high desert soils are high in alkalinity, especially those with heavy clay. Add soil sulfur in the amount recommended on the label to bring your soil pH between 6.0 and 6.8.
Work 20 lbs. of iron chelate per 2,000 square feet of garden bed surface area into the soil to improve nutrient uptake and prevent iron chlorosis.
Start tender plants, like tomatoes and peppers, indoors in February so they will have a good head start. Do not plant them outside until after your area's last predicted frost date, which will be in May for most high desert locations. Check with your county extension agent to find out frost dates for your area.
Harden off your starts. Place them outdoors in a sheltered location, in partial sun, during the daytime for at least a week prior to planting.
Plant your starts in the garden soil at the same level they were growing. Create a 4-inch deep well in the soil around each plant using your hands. Connect multiple wells in a row so that water will flow to each plant in the garden. Cover all exposed soil in your garden with a 6-inch deep layer of organic mulch, avoiding 2 or 3 inches around each plant's stalk. Maintain this mulch layer throughout the season to reduce moisture loss from evaporation and moderate fluctuations in soil temperature.
Fill each well to the rim at planting time, allow it to drain, then repeat the process once more. Water your plants deeply every few days for the first two weeks after planting, by filling the water wells and allowing them to drain twice.
Protect your newly planted starts with a loose layer of straw mulch if temperatures are predicted to drop below 45 degrees F.
Apply a balanced foliar fertilizer to your plants monthly in the early morning. Follow the instructions on the label to prepare the correct dosage. Fill a spray bottle or garden sprayer with the fertilizer and spray the tops of the leaves lightly. Look for organic formulas that include sea kelp or molasses.