Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can estimate when it's a good idea to plant pearl onions in Northfield by looking at 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 get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant pearl onions in Northfield 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. If you wait any later than that and your pearl onions may not have a chance to fully mature. You can get started a few weeks earlier by starting your pearl onions indoors.

Last Frost Date

The average date of last frost is May 15 in Northfield. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Northfield may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Northfield last frost occurs after May 15 be ready to cover your pearl onions in the event of a surprise late frost.

USDA Zone Info for Northfield

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 Northfield

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