When to Plant Tomatoes in Wisconsin?

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Quick Answer: Best Time to Plant Tomatoes in Wisconsin

In Wisconsin, try transplanting tomatoes after May but do not plant late otherwise, tomatoes will not set fruit. To minimize the risk of weeds, mulch and stake the tomato plants. To warm the soil, supplement the soil with organic matter. On extreme chilly nights, put the plants under shade at night.

This is a comprehensive guide to growing tomatoes in Wisconsin considering all important factors including, average frost dates, optimum temperature, humidity, and other environmental factors.

Let us get started!

Best Time to Plant Tomatoes in Wisconsin

The best time for planting tomatoes in Wisconsin depends on the type of variety, its ripening, weather conditions, and frost.

The indeterminate variety grows up to 15ft. tall and fruits ripen until the first frost. Determinate is small and grows up to 3-4ft high. The fruits ripen only once in the season.

The transplants must be sturdy enough before outdoor planting. To achieve this, consider planting the seeds in February. Start indoor seedlings seven to eight weeks before the expected last frost.

Frost Start-End Dates in Wisconsin

CityFirst Frost DateLast Frost Date
GraftonOct 10May 02
Saint FrancisOct 17Apr 29
GillettSep 24May 22
Wild roseSep 28May 15

In February and March, sunlight is not available so look for artificial means of light for germination.

South-facing windows are the best medium to provide natural sunlight to the plants.

Do not put the plants under cold temperature at any point in their stage. Warm the soil enough to compensate for the chilly temperature outside.

Water your plants just in a moderate amount. Avoid damping of the soil. Outdoor plants might cover their water needs through rainfall but indoor plants need spraying water once in a while.

The temperature range must be between 60-80 degrees F. The humidity must be moderate and rainfall should not be too much.

Transplant the tomatoes in late spring. May is usually ideal for Wisconsin but for safety, consider planting from the 1st of June.

Start harvesting the tomatoes in September.

Check out this video for Wisconsin tomato planting-

How to Take Care of Tomatoes in Wisconsin

Tomato is a delicate vegetable and needs to get protected from frost and cold nights. Cover the plants using fabric or put them under some shade. Harvest the tomato fruits before frost season begins.

Harvest the tomatoes before they are overripe. It will reduce the chance of fruits undergoing rotting. To check to ripen, consider the firmness of the tomato.

Harvest green tomatoes and let them ripe inside. You can freeze the ripe tomatoes until used.

Remove the dead branches and suckers. It can enhance circulation and allow more sunlight. Pruning is strictly for indeterminate plants only.

Water the plants through the drip irrigation system. Water the roots of the plants. At least provide one or two inches of water per week infrequently. Avoid wetting the foliage and stem.

Flowering and Fruiting are easily affected by the presence of a high amount of Nitrogen and less watering.

Supplement the fertilizer with less Nitrogen and more phosphorus, and potassium.

Fertilizer must be added to the soil mix. It will increase the rate of germination. Seedlings usually require high nitrogen so fertilizer must be added accordingly. You can use 5-10-5 fertilizer or any fertilizer less rich in Nitrogen.

Mulching must be spontaneously done after transplanting. With a thick layer of newspaper complemented with leaves, the straw will reduce weed growth and enhance the nutrient level of the soil.

Check out this video for raising beds for tomatoes –

Mulching is a great way of maintaining soil moisture of the soil. It prevents the splashing of water.

To increase airflow between the plants, trellis the tomatoes. Buy commercially available cages or trellis or build one according to plant height and garden area.

Maintain a space of 18-24 inches between the rows.

Perform a soil test from qualified labs and supplement the soil accordingly. The optimal pH of the soil is 6.2 to 6.8.

Add limestone or wood ash to improve the pH. To increase the calcium levels of the soil, add some eggshells to the soil.

Best Tomato Varieties to Grow in Wisconsin

For Wisconsin – The best Indeterminate Type – Cherry tomatoes and the best Determinate Types – Roma and Patio Tomatoes.

Other varieties are Early Girl, Beefsteak, Ace 55, Yellow Plum, Hillbilly, Peche, Amish paste, and Snowberry.

The tomato variety must be resistant to V, VF, LB, and TSWV. Grafted tomatoes help provide protection against diseases.

In the End

I hope this detailed guide will help you to grow tomatoes in Winsconsin considering its climate and soil.

Do share this with your friends and family who love growing tomatoes!