Growing tomatoes can be difficult in the hot Las Vegas desert

The tomato is by far the United States' favorite vegetable, because it is such a heavy producer and it meets so many of the family's needs. But we have difficulty growing it in Las Vegas because of the summer heat.

To overcome this problem, forget about the familiar long-season varieties such as Big Girl and Beefsteak. By the time they get ready to set fruit, it's too hot. We have to grow the smaller-fruited, quick-producing types such as Cherry, Early Girl, Patio and Better Boy. Note on the tag the number of days from planting to harvest. Anything from 60 to 80 days is suitable but those that produce in 70 days or less are best.

When to plant: Plant your tomatoes by the end of March; in fact, the earlier the better. You may want to plant again in August for a late-season crop. Encourage rapid growth with good soil preparation. Work copious amounts of humus into dead soil so roots can mine for food. Don't overdo nitrogen fertilizers; they can stimulate too much growth and blow off the blossoms. At planting, drench each rootball with a pint of starter solution, which is rich in phosphorus, and stimulates root growth. Thereafter, avoid letting the plant dry out.

The flowers: Tomato flowers drop when night temperatures fall below 55 degrees. You can overcome this by spraying the blossoms with Tomato Bloom Set to initiate fruit set. Bees do not pollinate tomatoes, so don't plan on them to do the job. Tomatoes stink; that's why bees go to other flowers.

Tomato flowers also fall off when day temperatures exceed 90 degrees. The blooms that set when it's colder don't when it's on the hot side. You can help set fruit by directing a strong force of water at the blossoms. The added moisture raises the humidity and lowers the temperature, so they set. Once it gets over 100 degrees, they won't set at all and the flowers will drop.

But don't give up and pull up your barren vines; once it cools, they will prodce a fall crop.

Plant in protected area: Plant tomatoes in a protected area with some shade to reduce the incidence of curly top virus and sunburn. We find leafhoppers, which carry this virus, do not visit shaded areas. But remember, tomatoes will not grow in dark places. If you do plant in direct sun, find ways to cover the plants. Close plantings also will allow the plants to protect themselves from the blistering sun.

Extend the growing season by planting tomatoes in pots and tubs. This allows you to protect them from the sun and the frost next fall.

Picking the best plants: Be sure to choose good plants. A high-quality plant is dark green with a sturdy series of leaves starting down low on a strong stem. Ideally, the plant should be about five to six inches high. Nurseries generally sell smaller plants in packs of six or eight; they are OK, too, but the single plants are larger and older and will produce sooner.

Look for plants that are evenly mature and sturdy. Forget any leggy plants that are discolored; these plants had no room to grow roots and always will struggle in the garden. Also make sure not to buy any plants infested with insects.

Planting your crop: Set the tomatoes deep in the soil, up to the first leaf branches. Better still, remove the lower leaves to plant even deeper. This encourages the stem to grow extra roots, making a stronger plant, provided it is in a well-prepared, fertile soil that is warm at root depth.

Once in the ground, a deep watering every three or four days is better than a daily, light sprinkling.

Keep the leaves and fruit off the ground in the interest of disease control. The easiest way to do this is to mulch under young plants with straw or hay. Thereaafter, be a lazy gardener with respect to tomatoes, and do not prune them. The excess foliage shades the plant, which increases fruit set and reduces splitting from the heat.

Handling the pests: Tomatoes are relatively pest-free; however, some pester them. Nematodes can be a problem in old garden soils. These tiny, wormlike creatures invade vegetable plant roots and cause them to swell and become distorted. This prevents plants from getting the needed nutrients, and yields go down. There is no chemical treatment for the home gardener. The best solution is to leave the garden soil vacant for a year and then add a lot of organic matter before reusing.

Some varieties of tomatoes, designated by the letters V.F.N. after their name, are resistant to verticillium wilt, fusarium wilt and nematodes. Always use tomatoes with these resistant genes in them so your chances of success will be much greater.

When you see caterpillars, such as tomato hornworms and fruit worms, pick them off the plants or spray with an organic spray called Dipel or Thuricide. If these don't work, use Sevin.

Blossom-end rot on the fruit and fruit cracking can be traced back to growth spurts caused by excessive heat and irregular watering. These conditions are common in Las Vegas. A deep soil well supplied with humus helps prevent this occurrence. I find smaller varieties are less prone than the longer-growing, larger-fruited kinds.

Linn Mills is a horticulturist for the University of Nevada Cooperative Extension. This column is adapted from his weekly column in the Review-Journal, and originally appeared on March 20, 1996.