When to Plant Tree onions in Sussex, WI

One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can estimate when it's a good idea to plant tree onions in Sussex by reviewing the USDA zone info.


Planting Calendar for Tree onions

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

Since tree onions are one of those plants that can tolerate a tiny bit of cold weather you can plant them a bit earlier in the year than other plants that might not handle the cold.

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 Sussex 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 grow to maturity. You can get started a little bit earlier by starting your tree onions indoors.

Last Frost Date

In Sussex the average date of last frost happens on April 15. You can expect an average low temperature of -20°F in the coldest months of winter.

Remember that USDA zone info for Sussex is just an average and the actual date of last frost changes from year to year. Half of the time in Sussex there is a last frost after April 15 so make sure that you are prepared to cover your tree onions if you have one of those late frosts.

USDA Zone Info for Sussex

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 Sussex

You may be interested in your other planting guides for Sussex.