When can I plant Onions in Zone 1a

One of the first steps we take when we are getting a good idea our gardening schedule is find our USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for our area.

In Zone 1a you can determine when to plant onions by reviewing the USDA zone info.


Planting Calendar for Onions

Frost tolerance for onions: Very tolerant of frost.
When you should plant them: Up to 7 weeks before last frost.

Since onions are very cold tolerant you can plant them a lot earlier in the year than other plants that might not handle the cold.

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

The earliest that you can plant onions in Zone 1a 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 onions and expect a good harvest is probably July. You probably don't want to wait any later than that or else your onions may not have a chance to fully mature. If you are starting your onions indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is June 15 in Zone 1a. It might get as low as -60°F during the coldest months of winter.

Since the USDA zone info for Zone 1a is just an average our actual date of last frost will vary from year to year. Since half of the time in Zone 1a there is a last frost after June 15 be ready to protect your onions if we have a late frost.

USDA Zone Info for Zone 1a

Here is the info for USDA Zone 1a.

Average Date of Last Frost (spring)June 15
Average Date of First Frost (fall)July 15
Lowest Expected Low-60°F
Highest Expected Low-55°F

This means that on a really cold year, the coldest it will get is -60°F. On most years you should be prepared to experience lows near -55°F.

Plants to Grow in Zone 1a

You may be interested in our other planting guides for Zone 1a.