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.

A common way of determining when you can plant dahlia is to look at the USDA zone info for Vail.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since dahlia require warm weather you must wait until after the last frost has passed before you can plant them.

The earliest that you can plant dahlia in Vail is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant dahlia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your dahlia may not have a chance to fully mature. If you are starting your dahlia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Vail. You should expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Vail may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Vail you get surprised by a frost after May 15 be ready to protect your dahlia in the event of a late frost.

USDA Zone Info for Vail

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Vail

You may be interested in your other planting guides for Vail.