Avid Southwest gardeners see August as a time to enjoy the beauty of summer annuals, the bounty of a summer garden harvest, and the shade of the early morning or late afternoon. Southwest gardeners also mark August as the traditional beginning of the fall vegetable garden. Some fall vegetables should be planted by seed as early as mid-August: squashes like acorn, butternut and Hubbard; zucchini; melons like “Crenshaw,” honeydew, and casaba; fall sweet corn; tomatoes; peppers; and green beans. And September marks the beginning of the fall vegetable planting season — the most abundant season in desert gardening. So, preparing the garden’s soil is on every vegetable grower’s August checklist.
Soil balance is the foundation for a delicious vegetable harvest come fall, including a neutral pH and balance of major and micro nutrients as well as bioactivity.
Soil pH in the Valley is typically alkaline, caused by our caliche soil as well as salt laden water. To lower the pH and later maintain the proper soil pH, apply a water-soluble soil acidifier like First Step Soil Acidifier. A pH or soil test is available at some reputable nurseries for very little cost and can tell you the current pH of your garden’s soil. Be sure that the test includes recommendations for fertilization. This can save you money in the long run since you have a prescription for only what is needed.
Another benefit of using First Step Soil Acidifier is the savings on water bills as well as eliminating the problem of standing water from irrigation. This opens the soil to allow water to penetrate quickly. What a huge benefit you can give to help eliminate West Nile Virus from mosquitoes breeding in stagnate water.
A soil’s nutrient content can have dramatic affects on a vegetable’s taste, plant vitality, root development and yield. Choose a balanced fertilizer containing all three major nutrients, nitrogen, phosphorus and potassium, but with a higher phosphorus content. In general terms, the nitrogen promotes plant growth and vigor, the phosphorus promotes fruiting and higher yields, and the potassium promotes cell strength and root development.
Micronutrients are important for a vegetable’s flavors, and the oils that carry the flavors and give the taste complexity. Soils low in micronutrients such as magnesium, copper, manganese, iron, zinc, etc., can be supplement with a micronutrient mix. Here again, an inexpensive soil test can be a valuable tool. Similar to the pH test, a soil test tells you the nutrient content of your soil and fertilizer choices and application rates can be tailored to your soil’s needs to create the ideal soil environment for your vegetables to grow. If you opt not to have your soil tested, follow the application rate for the fertilizer you choose.
Many people prefer organic fertilizers for growing vegetables. If you choose to go organic, you will need a number of products. Nitrogen is obtained from numerous kinds of manure including guano, bat manure that has the highest nitrogen rate. Blood meal is also a source of nitrogen. Greensand is a source of potassium, and phosphate rock and bone meal are a source of phosphorus and calcium. A nursery professional can assist you with choosing organic fertilizers and proper application rates.
Finally, add organic matter to the soil in the form of mulch or compost. Organic matter stimulates bioactivity like microbes that help in the root’s uptake of nutrients and worms that keep the soil nicely turned. Organic matter also helps the soil retain moisture. Every year, add an inch of organics to the soil’s surface and work it into the soil with a spade or tiller. If your soil is particularly hard, apply a two-inch layer each year. Then after planting, applying a thin layer of fine ground mulch or compost to the surface to retain moisture and protect seeds from birds and sun. And if the birds are eating your seedlings after germination, use a grow blanket (aka frost blanket) over the vegetable beds. A grow blanket is a geo-textile fabric that you can find at nurseries; it is designed to let light and air flow freely through the fabric.
• Kari Petterson is with Gardener’s World Nursery, 3401 E. Baseline Road. Reach her at (602) 437-0700.