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

By using the USDA zone info for Thornton it's a good idea to determine when it's a good idea to plant artemesia.

Planting Calendar for Artemesia

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

Artemesia do ok in mild cold which means that you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant artemesia 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 artemesia and expect a good harvest is probably August. Any later than that and your artemesia may not have a chance to grow to maturity. If you are starting your artemesia indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Thornton the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

It's important to remember that USDA zone info for Thornton is just an average and the actual date of last frost is different every year. Half of the time in Thornton there is a last frost after April 15 so make sure that you are prepared to cover your artemesia 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.