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

In Thornton you can estimate when it's possible to plant hosta by reviewing the USDA zone info.

Planting Calendar for Hosta

Frost tolerance for hosta:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Hosta tend to make it in moderate cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant hosta 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 hosta and expect a good harvest is probably September. Any later than that and your hosta may not have a chance to really do well. Starting your hosta 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. It might get as low as -15°F during the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Thornton and it is different every year. Half of the time in Thornton you get a frost after April 15 so always be ready to cover your hosta if you have 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.