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.

In Crookston you can determine when you can plant thunbergia by checking out the USDA zone info.

Planting Calendar for Thunbergia

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

Since thunbergia do not do well in cold weather it is necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant thunbergia in Crookston 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. Starting your thunbergia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Crookston the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Crookston may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Crookston you get a frost after May 15 so just be sure to be ready to protect your thunbergia in the event of one of those late frosts.

USDA Zone Info for Crookston

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Crookston

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