When to Plant Onions in Slinger, WI

One of the first steps you take when you are figuring out 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.

By referring to the USDA zone info for Slinger you should be able to estimate when it's a good idea to plant onions.


Planting Calendar for Onions

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

Onions do well in pretty solid cold which means that you can plant them much earlier in the year than more sensitive plants.

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 Slinger is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant onions and expect a good harvest is probably September. If you wait any later than that and your onions may not have a chance to really do well. You can get started a little bit earlier by starting your onions indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Slinger. In the coldest months of winter you should expect an average low temperature of -20°F.

Since the USDA zone info for Slinger is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Slinger last frost occurs after April 15 so make sure that you are ready to protect your onions if you have a surprise late frost.

USDA Zone Info for Slinger

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 Slinger

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