One of the best tools that you have as gardeners to help us figure out 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.

It's possible to determine when it's the best time to plant salpiglossis by referring to the USDA zone info for Houston.

Planting Calendar for Salpiglossis

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

You can not plant salpiglossis until after the last frost because they require warm weather.

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

The last month that you can plant salpiglossis and expect a good harvest is probably September. You probably don't want to wait any later than that or else your salpiglossis may not have a chance to fully mature. Starting your salpiglossis indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Houston the average date of last frost happens on February 15. In the coldest months of winter you should expect an average low temperature of 20°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Houston and it changes from year to year. Since half of the time in Houston it frosts late in the year after February 15 be ready to protect your salpiglossis if you have one of those late frosts.

USDA Zone Info for Houston

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°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 25°F.

Plants to Grow in Houston

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