The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of getting a good idea when to plant welsh onion is to check out the USDA zone info for Bolingbrook.

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.

Welsh onion do ok in a tiny bit of cold which means that you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant welsh onion in Bolingbrook 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. You probably don't want to wait any later than that or else your welsh onion may not have a chance to really do well. Starting your welsh onion indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Bolingbrook. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Bolingbrook is an average the actual date of last frost changes from year to year. Since half of the time in Bolingbrook last frost occurs after April 15 be ready to cover your welsh onion if you have one of those late frosts.

USDA Zone Info for Bolingbrook

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Bolingbrook

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