When to Plant Cosmos in Zone 2a

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.

It's a good idea to figure out when you can plant cosmos by looking at the USDA zone info for Zone 2a.


Planting Calendar for Cosmos

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

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

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

The earliest that you can plant cosmos in Zone 2a 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 cosmos and expect a good harvest is probably August. You probably don't want to wait any later than that or else your cosmos may not have a chance to fully mature. Starting your cosmos indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Zone 2a. In the coldest months of winter you should expect an average low temperature of -50°F.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Zone 2a and it is different every year. Since half of the time in Zone 2a it frosts late in the year after May 15 be ready to cover your cosmos in the event of one of those late frosts.

USDA Zone Info for Zone 2a

Here is the info for USDA Zone 2a.

Average Date of Last Frost (spring)May 15
Average Date of First Frost (fall)August 15
Lowest Expected Low-50°F
Highest Expected Low-45°F

This means that on a really cold year, the coldest it will get is -50°F. On most years you should be prepared to experience lows near -45°F.

Plants to Grow in Zone 2a

You may be interested in your other planting guides for Zone 2a.