When to Plant Dahlia in Zone 3a

Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant dahlia in Zone 3a should be estimated by referring to the USDA zone info.


Planting Calendar for Dahlia

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

You should not plant dahlia until after the last frost when the weather gets warmer because they do not do well in cold weather.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant dahlia
Possibly ok, but a risky time to plant dahlia
Probably not a good time to plant dahlia

The earliest that you can plant dahlia in Zone 3a 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. Any later than that and your dahlia may not have a chance to grow to maturity. If you are starting your dahlia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Zone 3a. You should expect an average low temperature of -40°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Zone 3a is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Zone 3a you get a frost after May 15 so always be ready to cover your dahlia if you have one of those late frosts.

USDA Zone Info for Zone 3a

Here is the info for USDA Zone 3a.

Average Date of Last Frost (spring)May 15
Average Date of First Frost (fall)September 15
Lowest Expected Low-40°F
Highest Expected Low-35°F

This means that on a really cold year, the coldest it will get is -40°F. On most years you should be prepared to experience lows near -35°F.

Plants to Grow in Zone 3a

You may be interested in your other planting guides for Zone 3a.