This article first appeared in the St. Louis Beacon, April 19, 2011 - Superior taste and the ability to take the heat of St. Louis summers have made the art of growing tomatoes into somewhat of a tradition among home gardeners. The National Garden Bureau has deemed 2011 the "year of the tomato," and now is the time for growers to begin prepping their gardens in anticipation of their first tomato plants.
Though tomatoes are typically a sturdy, vigorous plant, more growers are finding it difficult to produce a "perfect" tomato. "The number of problems gardeners have had has risen in recent decades," said Chip Tynan, manager of the Missouri Botanical Garden's Horticulture Answer Service. Problems with watering, spacing and overused soil can result in less-than-ideal fruit.
Tynan said many of these issues are related to a lack of understanding of what it takes to maintain good soil. "(There's) no such thing as virgin soil anymore, soils have been disturbed for generations now," he said.
One option for rejuvenating soil is growing a cover crop in the area where tomatoes will be planted in the spring. Chris Wimmer, an organic farmer with the Farm at Kraut Run, plants a crop called hairy vetch in the fall. The vetch inhibits soil-borne diseases and fertilizes the soil. At the end of the vetch's season, Wimmer lets the plant dry out and sit right where it grew. The dried vetch can then be transformed into nutrient-rich mulch for the spring.
Tynan said another way a gardener can add organic matter is to look around their own garden for yard waste and turn it into homemade compost. Commercial composts are available, but these sources may not be completely free of pesticides or herbicides.
Along with soil, gardeners need to consider the amount of sunlight the plants will receive. Kathie Hoyer of Bowood Farms said the plants need at least six hours of sun per day or they won't produce fruit. Around the peak of the summer, the plants may stop producing fruit for a short period. "(The plants) don't have flowers when it gets really hot, but they'll come back again once it cools off a little bit," Hoyer said.
Researching plant varieties that do well in a Missouri climate can help yield better fruit. Bowood recommends trying a hybrid, heirloom, cherry and one new variety each year. "If something catches your eye, just go for it," Hoyer said. Hoyer recommends a new variety called Defiant, which combines a high yield with great taste and superior disease resistance.
For gardeners with small yards, Wimmer recommends the Wisconsin 55 and the Celebrity varieties. Druzba and Tropic are two new varieties Wimmer is growing this season because they are recommended for hot, humid and disease-prone gardens.
The comeback of heirlooms is a new trend in tomato growing, which Tynan said can be a good and a bad thing. Heirloom tomatoes provide great taste, but some heirlooms only do well in certain climates and the plants have a much smaller yield than other varieties.
Patience and Space
A resource on which varieties do well in Missouri's climate is the University of Missouri vegetable planting calendar, which contains lists for any at-home crop.
For gardeners in central Missouri, the recommended time to put tomato plants in the ground is not until May 10-20. "It's fun to try to get the first tomato, but your plants could suffer for it," Tynan said. Tomato plants like warm soils and temperatures in the root zone should be at least 60 degrees.
Tomato plants that go in too soon will stay stagnant if the ground is too cold, and this can affect how much fruit the plant produces. Since central Missouri's tomato-growing season is so long, it's more important to have plants producing in the fall than to be the first on the block to show off a tomato.
"Once you put them in the ground they really take off in the heat of the summer," Hoyer said. Most tomato plants begin producing fruit in June and continue to yield fruit into mid-October.
When it's time to plant, all of the leaves but the top two or three on the tomato transplant need to be removed, and then the stem is buried all the way up to the leaves. "Tomatoes are the only plant we tell people to do this with," Hoyer said. Burying the stem deeply yields a stronger plant that can withstand winds and heavy rain.
Once the plants are in the ground, they need consistent watering in the growing period, but not as much once the plant begins to produce fruit.
Soaker hoses and drip irrigation systems are best for tomatoes because they deliver water right at the root line. "One of the biggest factors in the spread of diseases is splashing water," Tynan said. Placing straw or hay around the base of the plants can help minimize splashing on the leaves. Wimmer recommends using a base of compost, which will help fertilize the plant, and a top layer of mulch.
Tomato plants only need to be watered at the root line or directly on the fruit, not on the leaves. If leaves stay wet for long periods of time, they become susceptible to diseases. And leaves dry off faster if the plants have enough space.
"It's counterproductive to plant too close together, it restricts airflow and circulation," Tynan said. The ideal spacing for plants is two and a half to three feet apart, so the leaves of fully mature plants do not touch one another.
Gardeners with small yards can avoid spacing issues by growing tomatoes in pots. Shorter varieties of the plant do well in a pot more than 10 inches in diameter, with one plant per pot.
If signs of disease do crop up, Wimmer said it's important to remove the infected part of the plant right away and to wash pruners after working with a diseased plant. "You can save a plant with early signs of disease if you're on top of it," he said.
Trying to produce the perfect tomato may take a little extra work, the results are worth the labor. "When you start gardening for yourself, (all food) tastes amazing," Wimmer said.
Erika Miller, a senior at Saint Louis University, is an intern with the Beacon.