Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Holtville should be used to determine when it's the best time 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.

It's probably not a good idea to plant thunbergia until after all chance of frost has passed because they require warm weather.

The earliest that you can plant thunbergia in Holtville is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant thunbergia and expect a good harvest is probably September. If you wait any later than that and your thunbergia may not have a chance to grow to maturity. Starting your thunbergia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Holtville. You should expect an average low temperature of 30°F in the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Holtville and it changes from year to year. Half of the time in Holtville there is a last frost after January 31 so be sure to be ready to protect your thunbergia in the event of one of those late frosts.

USDA Zone Info for Holtville

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Holtville

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