The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Thornton should be reviewed to determine when you can plant salpiglossis.

Planting Calendar for Salpiglossis

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

It's probably a bad idea to plant salpiglossis until after all chance of frost has passed because they require warm weather.

The earliest that you can plant salpiglossis in Thornton 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 salpiglossis and expect a good harvest is probably August. If you wait any later than that and your salpiglossis may not have a chance to fully mature. You can get started a little bit earlier by starting your salpiglossis indoors.

Last Frost Date

In Thornton the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Thornton may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Thornton you get a frost after April 15 so be sure to be ready to cover your salpiglossis in the event of a late frost.

USDA Zone Info for Thornton

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°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 -10°F.

Plants to Grow in Thornton

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