One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to determine when it's possible to plant thunbergia by reviewing the USDA zone info for Forest Lake.

Planting Calendar for Thunbergia

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

Thunbergia require warm weather which tells us that you must wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant thunbergia in Forest Lake is May. However, you really should wait until June 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. If you wait any later than that and your thunbergia may not have a chance to really do well. You can get started a little bit earlier by starting your thunbergia indoors.

Last Frost Date

On average the last frost has passed is on May 15 in Forest Lake. In the coldest months of winter you can expect an average low temperature of -25°F.

Remember that USDA zone info for Forest Lake is an average and the actual date of last frost is different every year. Since half of the time in Forest Lake last frost occurs after May 15 be ready to cover your thunbergia in the event of a surprise late frost.

USDA Zone Info for Forest Lake

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Forest Lake

You may be interested in your other planting guides for Forest Lake.