When can I plant Tree onions in Zone 1a

Before planting it is a good idea to find our USDA Zone info to determine our garden schedule. 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 tree onions in Zone 1a should be estimated by using the USDA zone info.


Planting Calendar for Tree onions

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

You can plant tree onions slightly earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

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

The earliest that you can plant tree onions in Zone 1a is June. However, you really should wait until July if you don't want to take any chances.

The last month that you can plant tree onions and expect a good harvest is probably July. If you wait any later than that and your tree onions may not have a chance to grow to maturity. If you are starting your tree onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost has passed is on June 15 in Zone 1a. We can expect an average low temperature of -60°F in the coldest months of winter.

Always keep in mind that USDA zone info for Zone 1a is an average and our actual date of last frost will vary from year to year. Since half of the time in Zone 1a we get surprised by a frost after June 15 be ready to protect your tree onions in the event of one of those late frosts.

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.