The USDA Zone info is a great tool for gardeners to help us determine 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.

The first opportunity to plant pearl onions in Winthrop Harbor should be estimated by using the USDA zone info.

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.

Pearl onions do ok in moderate cold which means that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant pearl onions in Winthrop Harbor 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 pearl onions and expect a good harvest is probably August. You probably don't want to wait any later than that or else your pearl onions may not have a chance to fully mature. Starting your pearl onions 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 Winthrop Harbor. In the coldest months of winter you should expect an average low temperature of -15°F.

Remember that USDA zone info for Winthrop Harbor is an average and the actual date of last frost changes from year to year. Since half of the time in Winthrop Harbor last frost occurs after April 15 be ready to cover your pearl onions in the event of a surprise late frost.

USDA Zone Info for Winthrop Harbor

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 Winthrop Harbor

You may be interested in your other planting guides for Winthrop Harbor.