One of the first steps you take when you are estimating 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.

The best time to plant thunbergia in Owatonna can be figured out by looking at the USDA zone info.

Planting Calendar for Thunbergia

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

Since thunbergia require warm weather it's necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant thunbergia in Owatonna 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 grow to maturity. Starting your thunbergia indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Owatonna. You can expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Owatonna is an average the actual date of last frost changes from year to year. Half of the time in Owatonna it frosts late in the year after May 15 so make sure that you are prepared to cover your thunbergia if you have a surprise late frost.

USDA Zone Info for Owatonna

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 Owatonna

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