Nationwide, tomatoes are the favorite vegetable of home gardeners. They are a warm-season crop, native to Central America. Therefore, they can be a challenge to grow in the cooler parts of northern Minnesota. Home gardeners in the coolest parts of Minnesota can successfully vine-ripen tomatoes if they follow these suggestions.

• Select short-season tomato varieties that have performed well in your area. The best test plot is your own garden.
• Select healthy, disease-free tomato plants for transplanting. Transplant them after the last frost in your area. In northern Minnesota this may be as late as June 15th.
• Use a high phosphorus, water-soluble fertilizer such as 12-52-17 or 15-30-15 diluted to 1/2 strength. These are often sold as powdered concentrates. Because of the short season it is important to get transplants established quickly.
• Stake and prune plants to a single leader or main stem. Remove the "suckers" or small stems that form at the junction of leaves and the main stem. This produces earlier and slightly larger fruit.
• Use plastic mulch on the soil and plastic row covers to accumulate heat during the early part of the season. Black polyethylene heats the soil and prevents weeds from growing. Clear polyethylene used as mulch increases soil temperatures the most. All perennial weeds and most annuals should be controlled before using clear mulch.
• Use plastic row covers or "mini-greenhouses" to accumulate heat. They give the plants a good start early in the season. Locate the tomato garden in an area of full sun. Reflected heat is also helpful. Once the soil has warmed, remove plastic mulch. Spread several inches of compost around the plants. Compost mulch helps control weeds and retains soil moisture. It also helps slow the spread of soil-borne diseases.
• Consider using hoop houses, also known as high tunnels. These are unheated, plastic-covered structures that provide an intermediate level of environmental protection and control as compared to open field conditions and heated greenhouses. Growers and researchers alike are impressed with the excellent weed, insect, and disease control within the tunnels.
• Water tomatoes at their bas
e. Avoid overhead sprinklers. Splashing water spreads disease. Reduce disease spread by watering plants early in the day.
• Finally, when frost threatens, bring indoors any tomatoes that have turned from dark to light green. Continue the ripening process inside.

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