One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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 common way of estimating when to plant leeks is to look at the USDA zone info for Herrin.

Planting Calendar for Leeks

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

Leeks do well in a bit of cold which means that you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant leeks in Herrin is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant leeks and expect a good harvest is probably September. 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 April 15 in Herrin. In the coldest months of winter you can expect an average low temperature of -5°F.

Since the USDA zone info for Herrin is an average the actual date of last frost is different every year. Since half of the time in Herrin last frost occurs after April 15 be ready to protect your leeks in the event of a surprise late frost.

USDA Zone Info for Herrin

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Herrin

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