Regional Gardening Reports :: National Gardening Association

In the Garden:
Southwestern Deserts
July, 2009
Regional Report

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Each of these silks represents a kernal of corn if pollination is successful.

Sweet Corn

Sweet corn fresh from the garden is one of life's delectable pleasures. However, modern hybrids require plenty of water, multiple fertilizer applications, and a watchful eye, especially if growing in the low desert. For some gardeners, that may require more "input" than you want to deal with, and if you're a Midwestern transplant, you may not be as satisfied with the quality of corn you grow here compared to "back home."

When I consider the route that Mother Nature planned for corn pollination, it amazes me that the end result is an ear of corn chock full of tidy rows of kernals. Numerous female ovaries are aligned on a cob; each ovary has a single "silk" strand attached that hangs out of the protective husk. Male flowers are the "tassels" growing at the top of the plant that produce pollen. A single grain of pollen must travel from a tassel down to the base of a silk to complete fertilization. Each fertilized ovary becomes one kernal of corn. If an ear is missing kernals, pollination was incomplete.

Pollen is usually viable from 12 to 20 days but may not last that long in the Southwest's hot, dry conditions. Silks may dry out before pollination as well. Because corn is wind-pollinated (rather than pollinated by bees and other insects), you can promote better pollen transfer from tassels to silks by grouping corn plants in grids or small circles rather than long rows.

For grid planting, a minimum of 4 rows by 4 rows with plants spaced 1 foot apart (16 square feet) is needed. Better pollination results from a larger grid, such as 12 feet by 12 feet. If space is very limited, plant in a circle with 6 to 10 plants.

In the low desert, corn can be sown in early spring, with a second sowing from mid-July through August to take advantage of the rainy monsoon season. Choose a variety that matures within 65 to 80 days. Before planting, amend soil with 4 to 6 inches of organic matter and add nitrogen and phosphorous fertilizers. Sow seeds one inch deep. Sow extra to allow for uneven germination and thin seedlings as needed.

Monitor soil moisture, never allowing soil to dry completely. If corn plants are stressed for water, leaves curl and tassels and silks dry out before pollination occurs. Layer at least 3 inches of mulch on top of the soil to help maintain moisture. When the plant has three to five leaves, apply a side dressing of nitrogen fertilizer (follow package recommendations) weekly for the next two or three weeks until flowering starts. Use as little as possible to maintain green foliage color.

When silks turn brown, it's a signal the corn may be ready to harvest. Feel the ear to see if kernals are developed, or pull back just the tip of the husk to look. The sooner corn reaches your plate after harvest the better, as sugars begin converting to starches soon after picking. Alternatively, head for your local farmer's market or roadside stand!

For something different, you might enjoy trying native corn varieties that are better adapted to desert conditions. Native Seeds/SEARCH ( offers many options. Read their descriptions, as not all are the "sweet" corn we think of today, but were grown for grinding into flour and long-term storage.

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