When can I plant Tree onions in Zone 5a

One of the first steps we take when we are making a decision about our gardening schedule is find our USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for our area.

A common way of estimating when it's a good idea to plant tree onions is to use the USDA zone info for Zone 5a.


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 barely cold tolerant.

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 5a is March. However, you really should wait until April 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 August. You probably don't want to wait any later than that or else your tree onions may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your tree onions indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Zone 5a. In the coldest months of winter we can expect an average low temperature of -20°F.

Since the USDA zone info for Zone 5a is not always accurate our actual date of last frost can change quite a bit from year to year. Half of the time in Zone 5a it frosts late in the year after April 15 so always be ready to protect your tree onions if we have a surprise late frost.

USDA Zone Info for Zone 5a

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-20°F
Highest Expected Low-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Zone 5a

You may be interested in our other planting guides for Zone 5a.