When to Plant Dahlias in Zone 3a

One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when it's the best time to plant dahlias in Zone 3a by referring to the USDA zone info.


Planting Calendar for Dahlias

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

It's probably not a good idea to plant dahlias until after the last frost has passed because they are not cold tolerant.

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

The earliest that you can plant dahlias 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 dahlias and expect a good harvest is probably August. If you wait any later than that and your dahlias may not have a chance to grow to maturity. Starting your dahlias indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Zone 3a the average date of last frost happens on May 15. It might get as low as -40°F during the coldest months of winter.

Always keep in mind that USDA zone info for Zone 3a is an average and the actual date of last frost changes from year to year. Half of the time in Zone 3a it frosts late in the year after May 15 so make sure that you are ready to cover your dahlias if you have a surprise late frost.

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.