One of the first steps you take when you are determining 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.

A way of making a decision about when to plant leeks is to use the USDA zone info for Zone 4a.

Planting Calendar for Leeks

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

Leeks are very cold tolerant which tells us that you can plant them much earlier than other frost tender plants.

The earliest that you can plant leeks in Zone 4a 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. You probably don't want to wait any later than that or else your leeks may not have a chance to really do well. If you are starting your leeks indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Zone 4a. In the coldest months of winter you can expect an average low temperature of -30°F.

Since the USDA zone info for Zone 4a 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 Zone 4a it frosts late in the year after May 15 be ready to protect your leeks if you have a surprise late frost.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zone 4a

You may be interested in your other planting guides for Zone 4a.