Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. 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 Grafton can be determined by reviewing the USDA zone info.

Planting Calendar for Thunbergia

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

It's probably a bad idea to plant thunbergia until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant thunbergia in Grafton 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. Any later than that and your thunbergia may not have a chance to fully mature. If you are starting your thunbergia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Grafton the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in the coldest months of winter.

It's important to remember that USDA zone info for Grafton may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Grafton it frosts late in the year after April 15 so make sure that you are ready to cover your thunbergia in the event of a surprise late frost.

USDA Zone Info for Grafton

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 Grafton

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