The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to estimate when it's a good idea to plant thunbergia by reviewing the USDA zone info for Grayslake.

Planting Calendar for Thunbergia

Frost tolerance for thunbergia:	Not tolerant of frost.
When to plant:	After the last frost.

You can not plant thunbergia until after the last frost because they require warm weather.

The earliest that you can plant thunbergia in Grayslake 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 thunbergia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your thunbergia may not have a chance to fully mature. You can get started a few weeks earlier by starting your thunbergia indoors.

Last Frost Date

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

Since the USDA zone info for Grayslake is not always accurate the actual date of last frost will vary from year to year. Half of the time in Grayslake you get a frost after April 15 so make sure that you are prepared to protect your thunbergia if you have a surprise late frost.

USDA Zone Info for Grayslake

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Grayslake

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