When can I plant Petunias in Zone 3a

One of the best tools that we have as gardeners to help us figure out our 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 our area.

The best time to plant petunias in Zone 3a should be figured out by looking at the USDA zone info.


Planting Calendar for Petunias

Frost tolerance for petunias: Tolerant of a very small amount of frost.
When you should plant them: Up to 3 weeks before last frost.

Petunias are one of those plants that can tolerate a tiny bit of cold weather which means that you can get them planted just a bit earlier than other plants that might not handle the cold.

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

The earliest that you can plant petunias in Zone 3a 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 petunias and expect a good harvest is probably August. You probably don't want to wait any later than that or else your petunias may not have a chance to really do well. If you are starting your petunias indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Always keep in mind that our actual date of last frost is an average because it is based on the USDA zone info for Zone 3a and it changes from year to year. Since half of the time in Zone 3a it frosts late in the year after May 15 be ready to protect your petunias in the event of 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 our other planting guides for Zone 3a.