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.

In Thornton you can estimate when you can plant poppies by referring to the USDA zone info.

Planting Calendar for Poppies

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

Poppies do well in mild cold which means that you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant poppies 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 poppies and expect a good harvest is probably September. If you wait any later than that and your poppies may not have a chance to really do well. Starting your poppies indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Thornton. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Thornton is not always accurate the actual date of last frost is different every year. Since half of the time in Thornton it frosts late in the year after April 15 be ready to cover your poppies 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.