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 reviewing the USDA zone info for San Marcos it's possible to determine when you can plant thunbergia.

Planting Calendar for Thunbergia

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

It's probably not a good idea to plant thunbergia until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant thunbergia in San Marcos 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 grow to maturity. 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 March 15 in San Marcos. It might get as low as 15°F during the coldest months of winter.

Since the USDA zone info for San Marcos is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in San Marcos last frost occurs after March 15 be ready to protect your thunbergia if you have a surprise late frost.

USDA Zone Info for San Marcos

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in San Marcos

You may be interested in your other planting guides for San Marcos.