One of the first steps you take when you are figuring out 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.

One way of determining when to plant thunbergia is to check out the USDA zone info for Washington.

Planting Calendar for Thunbergia

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

You really shouldn't 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 Washington 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. Starting your thunbergia indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Washington the average date of last frost happens on March 15. You can expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Washington is just an average the actual date of last frost is different every year. Since half of the time in Washington it frosts late in the year after March 15 be ready to cover your thunbergia in the event of one of those late frosts.

USDA Zone Info for Washington

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Washington

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