When can I plant Delphinium in Zone 3a

One of the best tools that we have as gardeners to help us determine 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 first chance to plant delphinium in Zone 3a should be figured out by using the USDA zone info.


Planting Calendar for Delphinium

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

You can plant delphinium just a tiny bit earlier in the year because they are barely cold tolerant.

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

The earliest that you can plant delphinium 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 delphinium and expect a good harvest is probably August. If you wait any later than that and your delphinium may not have a chance to fully mature. You can get started a little bit earlier by starting your delphinium indoors.

Last Frost Date

On average the last frost is on May 15 in Zone 3a. In the coldest months of winter we should expect an average low temperature of -40°F.

Just be sure to remember that our actual date of last frost is just an average because it is based on the USDA zone info for Zone 3a and it can change quite a bit from year to year. Half of the time in Zone 3a we get surprised by a frost after May 15 so make sure that you are ready to protect your delphinium in the event of a 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.