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The secrets of growing tomatoes

By Staff | Apr 1, 2011

“You cannot plant a tomato plant too deep. If the tomato is taller than 6 inches, make a deeper hole.” —Mary Beth Day Polk?County master gardener

What are purple, orange, yellow, green and red, come in multiple shapes and sizes and annually leave gardeners either bursting with pride or sulking in defeat?


From Mary Beth Day’s perspective, a bountiful crop of tomatoes ought to be one of the easiest plants to grow in one’s garden each year. Of course, Day is not just a garden-variety grower; she’s a Polk County master gardener. But she insists anyone can grow tomatoes with just a little preparation at planting time and some timely watering throughout the growing season.

Heirloom or hybrid?

Tomato plants and seeds come in two categories: heirloom or hybrid. Heirloom tomatoes are the open-pollinated cultivars of tomatoes and come in all sorts of colors, shapes, sizes and flavors. Hybrid tomatoes involve crossing two different lines of tomatoes. They generally are more disease resistant than heirloom tomatoes and have more uniform size and color. “They’re both excellent, they just have different tastes. Heirlooms have more taste,” Day said.

Richard Jauron, an Iowa State University Extension horticulture specialist, said “hybrid tomatoes generally produce more fruit, but either type of plant grows well in Iowa.

“They’re both easy to grow,” Jauron said.

Next, a gardener needs to decide whether to plant determinate or indeterminate seeds. A determinate seed will produce all of its tomatoes at once and then is done for the season. An indeterminate seed will produce the first crop of tomatoes, and continue for as long as growing conditions allow. “I like to can and I don’t like to can all year, so I plant a determinate,” Day said.

Start growing inside

To lower one’s costs and get a gardening fix in early, Day suggests starting with seeds of either hybrids or heirlooms and growing them inside. Gardeners can go to local garden stores or there’s a huge variety online.

Day likes the totallytomatoes.com website. There’s still a narrow window of opporunity to start a tomato plant from seed and get it planted in time for the start of the outdoor growing season.

Growing a plant inside only requires a window with abundant sunlight and a simple container.

“Tomatoes are very easy to start in the house. You can use whatever (container) you’ve got,” she said. Egg cartons, plastic foam cups, or empty flowerpots all work well. Then, just plant the seed in potting soil, water regularly, and wait for it to grow.

Around the second week in May, tomatoes generally are ready to go in the ground and are safe from freezing temperatures. Jauron, the Iowa State horticulturist, said planting after May 10 reduces the risk of a frost to just 10 percent. If freezing temperatures are forecast after planting, tomatoes can survive if they’re covered.

Plant smart

Pick a spot in the yard that receives a minimum of six hours of sun a day, but more sun is preferable. Tomatoes also want well-drained soil. Tomatoes need to have only about six inches of the plant above the ground.

“You cannot plant a tomato plant too deep,” Day said. “If the tomato is taller than 6 inches, make a deeper hole.”

Starter tomato plants from a garden center or other local retailer will work fine, too. However, those retailers generally don’t have the variety of tomatoes that one could find in a seed catalog, Day said.

She also recommends adding a tomato cage at the same time the tomato is planted. The cage provides support for the plant.

“If they’re in a cage, they grow upright and they’re easier to pick,” Day said.

Pick the right fertilizer

Once the tomatoes are planted, some gardeners will be tempted to fertilize them right away. Nothing can ruin your crop of tomatoes faster than using the wrong fertilizer.

“If you fertilize, you want to use a tomato fertilizer, so it will concentrate on setting the bloom and growing tomatoes for you. Otherwise, you’ll have a big beautiful tomato plant and you won’t have any tomatoes,” Day said. Generic fertilizers, such as those used for the lawn, have too much nitrogen for a tomato and focus the growth in the wrong part of the plant.

Tomatoes need adequate water but otherwise don’t need much attention, Day said. In hot and dry weather, tomatoes may need watering every two to three days or weekly in normal conditions. Although maturity dates vary, many plants will produce tomatoes within 60 days.

When the time comes, Day recommends a taste-off with each variety of tomato, to determine the favorite among family or friends. “There’s lots of things to do with tomoatoes. They’re fun,” Day said.

Hortline to the rescue

Although tomatoes are supposed to be easy to grow, there are resources available by e-mail, phone and the internet when gardeners run into problems. Iowa State University offers a phone hotline, called the hortline at (515) 294-3108.

One can call about gardening or other horticulture issues from 10 a.m. to noon and from 1 p.m. to 4:30 p.m. Monday through Friday.

Jauron, the horticulturist, handles many of the calls himself

Questions can also be sent to hortline@iastate.edu.

Iowa State’s Extension Service also has extensive information at its web site at www.extension.iastate.edu under the “store” tab at the top of the page.

Contact Dave DeValois at dwdevalois@yahoo.com.

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