Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to determine when it's the best time to plant garlic by referring to the USDA zone info for Thornton.

Planting Calendar for Garlic

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

Garlic are one of those plants that can tolerate quite a bit of cold weather which means that you can plant them a quite a bit earlier than more sensitive plants.

The earliest that you can plant garlic 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 garlic and expect a good harvest is probably September. You probably don't want to wait any later than that or else your garlic may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your garlic 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.

Since the USDA zone info for Thornton is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Thornton you get surprised by a frost after April 15 so always be ready to cover your garlic if you have one of those late frosts.

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.