How to Grow Tomatoes in Kansas

Tomatoes are among the most popular vegetables to grow in the home garden. The two most common reasons for tomato failure in Kansas are planting them too early before temperatures are sufficiently warm, and not providing adequate moisture, especially during hot, windy weather. Kansas gardeners with sandy soils should monitor soil moisture frequently, since these soils tend to dry out quickly.

Tomato plants

5-10-10 granular fertilizer

Row cover or cloche

Compost, grass clippings or straw

Buy dark green, compact plants, selecting disease-resistant varieties if possible. Fusarium wilt is the most common tomato plant disease in Kansas, according to Kansas State University, while nematodes affect tomatoes in areas south of Interstate 70.

Hand-broadcast a complete garden fertilizer on the soil at a rate of 1 to 2 lbs. per 100 square feet of soil. Dig the soil with a shovel to a depth of 8 inches or use a rototiller. Avoid fertilizers high in nitrogen, which encourage lush vegetative growth with few fruits. The first number on the fertilizer box indicates the nitrogen level. It should be half the level of the other nutrients, i.e. 5-10-10.

Plant tomatoes when the daytime temperatures are above 70 degrees F and all chance of frost is passed. According to Kansas State University, in southeastern Kansas, plant tomatoes early-to-mid April; in eastern and central Kansas, plant tomatoes from late April to early May. In northwest Kansas, plant tomatoes after May 15. Cover the tomatoes with a row cover or cloche if cold weather threatens.

Water tomato plants at least weekly, as needed to keep the soil evenly moist. Don't allow the soil to dry out between watering and avoid watering it until it is soggy, which contributes to blossom-end rot. Apply a 2- to 3-inch layer of compost, grass clippings or straw around the base of the plants to minimize weed growth and conserve moisture.

Monitor tomato plants for disease and pest problems. Consult a local county extension office for help in identifying and treating specific problems. Good cultural practices, such as selecting disease-resistant plants and watering tomatoes evenly and consistently prevent many problems. Remove any dead or diseased plant material, hand-pick and destroy tomato hornworms and avoid the use of pesticides that kill ladybugs and lacewings, since these predatory insects help eliminate pests.

Twist the tomatoes gently to remove them from the plants when they are ripe, or almost ripe (pink to bright red, depending on the variety). If a frost threatens, pick the green tomatoes and lay them in a single layer in a box. Place them in a cool, dark place, such as a basement, to ripen.

Popular tomato varieties for Kansas gardens include Merced, Sun Start, Daybreak, Celebrity, Cherry Grande and Roma.

Tomatoes are sun-loving vegetables. Plant them in a location that receives at least eight hours of sunlight per day.

While tomatoes can be left to sprawl on the ground, staking or caging them keeps them tidy and compact and may decrease the spread of soil-borne diseases. Caged tomatoes also take up less room in the garden. They produce fewer fruits than those left uncaged, but the fruits are usually larger and of better quality. Prune the suckers that grow between the main stem and the branches, according to Kansas State University. These soft, vegetative growths divert energy from producing fruit.

When hot Kansas weather arrives, tomatoes may drop their blossoms, failing to produce fruit. The ideal temperature for setting and ripening fruit is between 68 and 77 degrees F. Warmer temperatures may temporarily delay fruit production, which will resume when cooler temperatures return.

Space tomato plants 18 to 24 inches apart, depending on the variety. Many varieties benefit from caging or staking. Indeterminate varieties grow on sprawling, robust vines that become a tangled mess when left untended. Cages also reduce the risk of soil-borne diseases.