The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 Commerce City you will be able to figure out when it's possible to plant dahlias.

Planting Calendar for Dahlias

Frost tolerance for dahlias:	Not tolerant of frost.
When to plant:	After the last frost.

Dahlias are not cold tolerant which tells us that you need to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant dahlias in Commerce City is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant dahlias and expect a good harvest is probably August. You probably don't want to wait any later than that or else your dahlias may not have a chance to grow to maturity. Starting your dahlias indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Commerce City is not always accurate the actual date of last frost will vary from year to year. Half of the time in Commerce City you get surprised by a frost after April 15 so make sure that you are prepared to cover your dahlias if you have a late frost.

USDA Zone Info for Commerce City

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 Commerce City

You may be interested in your other planting guides for Commerce City.