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

You will be able to determine when it's a good idea to plant welsh onion by reviewing the USDA zone info for Sun Prairie.

Planting Calendar for Welsh onion

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

Since welsh onion are one of those plants that can tolerate a tiny bit of cold weather you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant welsh onion in Sun Prairie 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 welsh onion and expect a good harvest is probably August. Any later than that and your welsh onion may not have a chance to really do well. If you are starting your welsh onion indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Sun Prairie the average date of last frost happens on April 15. It might get as low as -20°F during the coldest months of winter.

Remember that USDA zone info for Sun Prairie may not be accurate from year to year and the actual date of last frost changes from year to year. Since half of the time in Sun Prairie there is a last frost after April 15 be ready to cover your welsh onion in the event of one of those late frosts.

USDA Zone Info for Sun Prairie

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 Sun Prairie

You may be interested in your other planting guides for Sun Prairie.