The USDA Zone info is a great tool for gardeners to help us figure out 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.

One way of estimating when it's the best time to plant thunbergia is to check out the USDA zone info for Harrisburg.

Planting Calendar for Thunbergia

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

You should not plant thunbergia until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant thunbergia in Harrisburg 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 grow to maturity. 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 Harrisburg. It might get as low as 5°F during the coldest months of winter.

Since the USDA zone info for Harrisburg is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Harrisburg last frost occurs after April 15 be ready to protect your thunbergia in the event of one of those late frosts.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Harrisburg

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