When to Plant Tomatos in Janesville, WI

The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Janesville can be reffered to in order to determine when to plant tomatos.


Planting Calendar for Tomatos

Frost tolerance for tomatos: Not tolerant of frost.
When to plant: After the last frost when the weather gets warmer.

Since tomatos do not do well in cold weather you need to wait until after the last frost before you can plant them.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant tomatos
Possibly ok, but a risky time to plant tomatos
Probably not a good time to plant tomatos

The earliest that you can plant tomatos in Janesville is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant tomatos and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tomatos may not have a chance to fully mature. If you are starting your tomatos indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Janesville. In the coldest months of winter you should expect an average low temperature of -20°F.

Just be sure to remember that USDA zone info for Janesville is an average and the actual date of last frost will vary from year to year. Half of the time in Janesville you get surprised by a frost after April 15 so always be ready to cover your tomatos if you have a late frost.

USDA Zone Info for Janesville

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-20°F
Highest Expected Low-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Janesville

You may be interested in your other planting guides for Janesville.