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Larry Sagers
A mélange of winter squash, including butternut, and pumpkins is for sale at a Utah farmers market.

Last week, we discussed the Three Sisters concept of gardening in which corn, squash and beans are planted simultaneously on a rounded mound of soil.

This week we'll take a closer look a the second sister: squash.

According to Iroquois tribal legend, squash grows over the mound, protecting her sisters from weeds and shades the soil from the sun with her leaves, keeping it cool and moist.

While that is true, squash has much more to offer. I consider the myriad types and cultivars of squash truly amazing. There's an almost endless selection of sizes, shapes and colors.

All squash plants are warm-season vegetables, so plant them after the danger of frost is past. Summer squash includes zucchini, yellow crook neck and many other cultivars.

These types of squash grow on more of a bush or non-vining plant and are picked before the squash fruits mature. Because the fruits do not need to be mature when picked, these produce crops quickly and keep producing for many weeks. Plant successive crops until mid-summer for an abundant, continuous harvest.

Winter squash typically grow on much larger plants that produce long vines. Winter squash are not harvested or eaten until they are mature. That means they are going to take several months to grow and mature, so plant them soon to give them a long growing season.

Grow squash in full sun and in fertile, well-drained soils when soil temperatures reach 65 degrees Fahrenheit. Use plastic mulches to enhance maturity and to conserve moisture. Black plastic mulch also helps control weeds. Avoid using organic mulches until soils reach at least 75 degrees Fahrenheit.

Squash are easily grown from seed, but some gardeners prefer transplants. Plant seed 1-2 inches deep. If you grow or buy transplants, they should have two to three mature leaves with well-developed roots. Avoid transplants that are too large and any that have started to vine.

Because the plants are large, they need adequate nutrition. Apply four to six cups of an all-purpose fertilizer (16-16-8 or 10-10-10) per 100 square feet before planting. When the plants start to vine or develop runners, side dress with one to two tablespoons of nitrogen fertilizer per plant.

While the plants are easy to grow, there are a few potential problems. Many gardeners complain that their plants look good and produce blossoms but not fruits.

Squash plants have male and female blossoms. Bees usually transfer the pollen from the male blossoms to the female blossoms so the fruit will form. With the shortage of bees in urban areas, you might have to do the bees' job.

Take a freshly opened male blossom and turn it inside out and rub it inside a freshly opened female blossom. You can also use an artist brush to transfer pollen from the male to the female blossom. Female blossoms are the ones with the small fruits behind them.

With all cucurbits (cucumbers, melons, pumpkins and squash), the first flowers that open are always male. The abundance of the male blossoms improves the chances that the female blossoms will get pollinated.

Keep your plants healthy by preparing the soil correctly and irrigating and fertilizing the plants as needed. Healthy plants are less attractive to pests and can tolerate some insect feeding.

Squash are not prone to numerous pests, but there a couple that cause problems. Squash bugs are the most difficult to control. They have piercing/sucking parts and emit a foul odor when disturbed.

The insect damages squash and pumpkin leaves and fruits, but the real problem is when they feed at the base of the stems. When that happens, they disrupt the ability of the plant to absorb water, and it will wilt and eventually die.

Adults overwinter in wood piles or around foundations and emerge in the spring to start laying eggs. A female can lay 250 eggs per season, so clean up hiding places to reduce their numbers.

Consider hand-picking the adults and nymphs and smashing egg clusters on leaves to reduce numbers. Start early in the season and check plants every two to three days.

The pests do not have many natural enemies because of their odor. Adult insects are not very susceptible to insecticides, so spray the young insects as soon as they hatch. Some registered insecticides include pyrethrins, rotenone, sabadilla, neem oil, malathion and carbaryl (Sevin).

There are no cultivars that are immune to squash bugs, but there are some that are less susceptible to the pests. Resistant kinds include Butternut and Royal Acorn. Sweet Cheese and Striped Green Cushaw are moderately resistant.

Susceptible kinds include Pink Banana and Black Zucchini, while Yellow Straightneck, Yellow Crookneck, Hubbard and pumpkin are considered highly susceptible to damage.

In spite of these and other pests, don't be discouraged. Tasty vegetables for summer and winter eating are your reward for planting and caring for these plants. Plant this member of the Three Sisters in your garden this year.

Larry A. Sagers is a horticulture specialist for the Utah State University Extension Service at Thanksgiving Point.