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.

In Thornton you can estimate when you can plant angel's trumpets by reviewing the USDA zone info.

Planting Calendar for Angel's Trumpets

Frost tolerance for angel's trumpets:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant angel's trumpets slightly earlier in the year because they do ok in moderate cold.

The earliest that you can plant angel's trumpets in Thornton 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 angel's trumpets and expect a good harvest is probably August. Any later than that and your angel's trumpets may not have a chance to really do well. You can get started a little bit earlier by starting your angel's trumpets indoors.

Last Frost Date

The average date of last frost is April 15 in Thornton. It might get as low as -15°F during the coldest months of winter.

Keep in mind that USDA zone info for Thornton is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Thornton there is a last frost after April 15 so make sure that you are ready to protect your angel's trumpets in the event of a surprise 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.