Start early when planting a bumper crop of tomatoes

     It's time to plant tomatoes. There's no other garden resident that's as eagerly awaited as the tomato. It is our most popular plant eaten as a vegetable and for good reason. The tomato is a heavy producer, and we each consume about 35 pounds in one form or another through the year.
      If you study seed catalogs, you'll find more than 300 varieties for sale. You can grow big brag-patch tomatoes; paste tomatoes for sauces; cherry or pear tomatoes; sweet, yellow, orange or red tomatoes; and even long-winter-storage types such as Long-Keepers. Many of these new hybrids boast more disease resistance, more vigorous growth and higher yields to improve your gardening pleasure.
      Most of us got our tomato-growing experience from cooler climates. Forget those experiences. Because of the heat, the tomato skins toughen, and they will lack in color when they ripen. So start early to improve your chances of success.
      Plant your tomatoes before April Fool's day; in fact, the sooner the better. If you wait much longer, it will be too hot when they start blooming and that causes the blossoms to abort.
      Sylvan H. Wittwer, the world's leading authority on greenhouse tomatoes, made an in-depth study of the tomato to improve its production. He found temperatures above 90 degrees for any length of time caused the blossoms to drop. We can expect more than 150 of those days this summer. He also found that when night temperatures stay above 76 degrees, flowers also abort. These hot temperatures burn up any food reserves tomatoes produce, and the flowers drop.
      Flowers will also abort when temperatures drop below 55 degrees for a length of time. He doesn't worry about this when he is growing tomatoes in the garden. He wants the early stages of the plant's growth to focus on root, stems and leaf development. If he wants to set fruit at this early age, he uses a growth hormone found at the nurseries. However, the fruit is not as sweet or as juicy.
      Wittwer, who lives in Moapa Valley, also found that tomatoes set best when the humidity stays above 40 percent, and you know we seldom have that in Las Vegas. The pollen simply flies past the female part of the flower, and that causes the flowers to drop.
      Frustrating, isn't it? One of the best ways to overcome these problems is to get your plants in early so the fruit will set before the hot conditions arrive.
      Here is a tip from a longtime tomato grower. Direct a strong force of water at the blossoms at least twice a day. The evaporating moisture lowers the temperature, raises the humidity and jars the pollen loose to improve fruit set. Of course, I must warn you that once the temperatures climb into the high 90s, misting is a waste of time.
      Despite what has just been said, choose a sunny location for tomatoes. Morning sun along with some relief from the evening sun becomes the best setting for them. When the temperatures do push into the 90s, provide some shade. One gardener has his cheesecloth ready to cover the plants when it gets around 85.
      Here are some of the more popular tomatoes that do well: Early-season varieties include Early Girl, Champion, Early Cascade and Spring Set; midseason include Better Boy, Celebrity, Fantastic, Ace 55, Floramerica, Heartland, Patio and Super Fantastic; late-season varieties include Ace, Beefsteak and Big Boy; miniatures include Small Fry, Sweet 100s Cherry and Tiny Tim. Your nursery will have others; give them a try.
      Select a tomato resistant to the common diseases in our soils. Look for the letters "VFN" after the variety's name. They indicate resistance to the following: V -- verticillium wilt, F -- fusarium wilt and N -- nematodes. Verticillium and fusarium wilts are both soilborne diseases that plug up the vascular system of plants, and they slowly die. Researchers breed resistance to another fusarium strain into tomatoes. It will look something like "VFFN" on the label. Nematodes are microscopic worms that feed on tomato roots, thereby robbing plants of food, causing them to die.
      Here is a myth we must dispel. Are there low-acid tomatoes? Many seed catalogs contain glowing sections about their low-acid tomatoes. The USDA collects data from all over the country and finds the acidity to be about the same no matter where the plants grow.
      Tomatoes thrive on a rich, well-drained soil -- something Las Vegas gardens lack. To get this ideal soil, thoroughly incorporate liberal amounts of organic amendment (compost, peat moss, etc.) and a fertilizer containing nitrogen and phosphorous (16-20-0 is an example) at 4 to 6 cups (2 cups equal a pound) per 100 square feet in the top of the tomato bed.
      Here's a tip: Before planting, dig a hole 3 inches deeper than normal and mix in 2 teaspoons of phosphate and replace the soil. When your tomato roots find the fertilizer, they will be off to a great season. Follow the planting with a deep irrigation, Do not water again until the plants show signs of wilt to encourage earlier fruit setting and harvesting or "bragging rights."
      Next, mulch under the tomatoes; it cools the plants to prolong fruit setting. It also conserves moisture and controls weeds. One longtime gardener mulches with alfalfa hay 3 inches deep. He's harvesting tomatoes all summer and seldom has any splits.
      Establish a regular watering schedule. Dig down occasionally to grab a handful of soil and give it the farmer's squeeze test. If the soil crumbles when opening your hand, irrigate; if not, wait a few days to check again. Tomatoes growing in containers require more waterings and feedings; never let the soil dry out completely.
      When plants are in full bloom, side-dress with a nitrogen-type fertilizer about once a month. Always water immediately after feeding.
      Learning opportunity. On Saturday at 9 a.m., the Master Gardener Guides are sponsoring a class for children ages 5 to 10 entitled "Tree Treasures." For details, call 258-3205.
     
      Linn Mills is a horticulturist for the University of Nevada Cooperative Extension.