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

You will be able to estimate when it's the best time to plant thunbergia by using the USDA zone info for Lowell.

Planting Calendar for Thunbergia

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

Thunbergia require warm weather which means that it's necessary to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant thunbergia in Lowell 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. If you wait any later than that and your thunbergia may not have a chance to grow to maturity. If you are starting your thunbergia indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost is on April 15 in Lowell. You should expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Lowell is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Lowell you get a frost after April 15 be ready to cover your thunbergia in the event of a surprise late frost.

USDA Zone Info for Lowell

Here is the info for USDA Zone 6a.

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

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

Plants to Grow in Lowell

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