The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant dahlias in Zone 1a should be figured out by reviewing the USDA zone info.

Planting Calendar for Dahlias

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

Dahlias do not do well in cold weather which tells us that it is necessary to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant dahlias in Zone 1a is June. However, you really should wait until July if you don't want to take any chances.

The last month that you can plant dahlias and expect a good harvest is probably July. If you wait any later than that and your dahlias may not have a chance to really do well. You can get started a few weeks earlier by starting your dahlias indoors.

Last Frost Date

The average date of last frost is June 15 in Zone 1a. It might get as low as -60°F during the coldest months of winter.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Zone 1a and it can change quite a bit from year to year. Half of the time in Zone 1a last frost occurs after June 15 so make sure that you are prepared to cover your dahlias in the event of one of those late frosts.

USDA Zone Info for Zone 1a

Here is the info for USDA Zone 1a.

Average Date of Last Frost (spring)	June 15
Average Date of First Frost (fall)	July 15
Lowest Expected Low	-60°F
Highest Expected Low	-55°F

This means that on a really cold year, the coldest it will get is -60°F. On most years you should be prepared to experience lows near -55°F.

Plants to Grow in Zone 1a

You may be interested in your other planting guides for Zone 1a.