One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Altoona it's a good idea to figure out when it's a good idea to plant thunbergia.

Planting Calendar for Thunbergia

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

Since thunbergia require warm weather you need to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant thunbergia in Altoona 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

The average date of last frost is April 15 in Altoona. In the coldest months of winter you should expect an average low temperature of -20°F.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Altoona and it changes from year to year. Half of the time in Altoona you get a frost after April 15 so just be sure to be ready to cover your thunbergia if you have a surprise late frost.

USDA Zone Info for Altoona

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Altoona

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