When to Plant Pearl onions in Sparta, WI

Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to figure out when it's the best time to plant pearl onions by looking at the USDA zone info for Sparta.


Planting Calendar for Pearl onions

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

You can plant pearl onions slightly earlier in the year because they are barely cold tolerant.

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

The earliest that you can plant pearl onions in Sparta is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant pearl onions and expect a good harvest is probably August. Any later than that and your pearl onions may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your pearl onions indoors.

Last Frost Date

On average the last frost has passed is on May 15 in Sparta. You can expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Sparta is not always accurate the actual date of last frost will vary from year to year. Half of the time in Sparta it frosts late in the year after May 15 so always be ready to cover your pearl onions in the event of one of those late frosts.

USDA Zone Info for Sparta

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)May 15
Average Date of First Frost (fall)September 15
Lowest Expected Low-25°F
Highest Expected Low-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Sparta

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