One of the first steps you take when you are getting a good idea 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.

By reviewing the USDA zone info for Thornton you will be able to estimate when to plant euphorbia.

Planting Calendar for Euphorbia

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

Euphorbia do ok in moderate cold which means that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant euphorbia 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 euphorbia and expect a good harvest is probably August. If you wait any later than that and your euphorbia may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your euphorbia indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Thornton. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Thornton and it is different every year. Since half of the time in Thornton last frost occurs after April 15 be ready to protect your euphorbia in the event of 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.