Tips for growing tasty tomatoes

The one thing Minnesotans dream most of during the snowy winter months: tomatoes. Juicy, ripe tomatoes fresh from the garden.

After what seemed like a very long winter, gardeners have been heading to the nurseries in a panic to plant. Before you do, take a deep breath, then take this little refresher course in tomato basics.

If you want to can tomatoes or make sauce, a determinate variety is best. Determinate tomatoes reach a certain size and stop growing. Their more manageable size makes them good candidates to plant in small spaces. They tend to ripen within the same time frame, which gives you a good number of tomatoes to work with all at once.

Indeterminate tomatoes, on the other hand, keep growing and producing throughout the season. They can sprawl up to 10 feet, so they need to be supported with cages or stakes and ties. These tomatoes are best sliced for sandwiches and salads or frozen to eat later.

Hybrids are a cross between two varieties that have been selected for their superior traits. Size, days to maturity and disease resistance are just a few of the qualities that are considered in hybridizing tomatoes. Heirlooms are old-fashioned tomatoes that come directly from seed.

The difference between them? In general, hybrids offer vigor and productivity, while heirlooms offer a wide variety of shape and color and, most important, great taste.

Many gardeners plant on the average last frost date, which is around May 15 in the Twin Cities metro area. But soil temperature is just as important as air temperature. And, in a cool spring like this one, it may take longer for soil to warm. Fifty-five degrees is the minimum soil temperature for successful tomatoes. To check the temp, you can buy a soil thermometer at your local garden center or pay close attention to the weather forecasts.

If you're planting in the ground, consider the days to maturity of the plants you choose. Early varieties are likely to be the best bet with a shortened growing season. Look for those that ripen within 55 to 65 days rather than 70 to 80. (Names with "early," "spring," "mountain" or references to Alaska, Russia or any other frigid place often are a clue the plant is an early maturing one.)

Amend your soil by adding compost and any granular fertilizer before you plant. It pays to plant your tomatoes deep. Nip off the lower leaves and bury up to two-thirds of the plant. Roots will grow along the stem underground and result in a stronger plant.

If your soil is heavy or tough clay, dig a trench along the side of the plant, lay part of the stem in the trench and cover it with soil. Gently bend the top of the plant up and leave it uncovered.

Consistent, deep watering is essential for tomatoes, which are fast-growing, high yielding plants. Irregular watering stresses the plants, which can lead to cracking or diseases, such as blossom end rot. Try to keep the soil moist to a depth of 6-8 inches.

Mulching will help conserve moisture, and it also helps prevent fungal disease. Water splashing up from the soil can spread spores that cause problems like blight and leaf spot. While these diseases generally don't kill a plant, they do affect yield. If you see yellowed and/or spotty leaves starting from the bottom of the plant, pick them off and toss them out. (Not in your home compost pile.)

You're not the only one looking forward to the first fruits of summer. Squirrels, raccoons and chipmunks have been known to sample them, too. Try hot pepper sprays or other animal repellents to keep them away. Remember, you'll need to reapply after a rain.

Slugs, hornworms and stinkbugs may take tiny bites that create blemishes on your tomatoes. Vigilant handpicking is the least toxic way to deal with these pests.