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

A way of figuring out when to plant leeks is to use the USDA zone info for Northfield.

Planting Calendar for Leeks

Frost tolerance for leeks:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant leeks a lot earlier in the year because they are very cold tolerant.

The earliest that you can plant leeks in Northfield 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 leeks and expect a good harvest is probably August. Any later than that and your leeks may not have a chance to grow to maturity. You can get started a little bit earlier by starting your leeks indoors.

Last Frost Date

The average date of last frost is May 15 in Northfield. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Northfield is an average the actual date of last frost changes from year to year. Since half of the time in Northfield there is a last frost after May 15 be ready to cover your leeks if you have one of those late frosts.

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.