One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Thornton you can determine when it's the best time to plant aubretia by using the USDA zone info.

Planting Calendar for Aubretia

Frost tolerance for aubretia:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant aubretia earlier in the year because they do well in cold.

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

Last Frost Date

The average date of last frost is April 15 in Thornton. In the coldest months of winter you should expect an average low temperature of -15°F.

Just be sure to remember that USDA zone info for Thornton is not always accurate and the actual date of last frost changes from year to year. Half of the time in Thornton it frosts late in the year after April 15 so just be sure to be ready to protect your aubretia 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.