The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Prospect Heights you can estimate when it's possible to plant leeks by looking at the USDA zone info.

Planting Calendar for Leeks

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

Leeks can survive in pretty solid cold which means that you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant leeks in Prospect Heights 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. Any later than that and your leeks may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your leeks indoors.

Last Frost Date

The average date of last frost is April 15 in Prospect Heights. It might get as low as -15°F during the coldest months of winter.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Prospect Heights and it will vary from year to year. Half of the time in Prospect Heights there is a last frost after April 15 so make sure that you are ready to cover your leeks if you have a surprise late frost.

USDA Zone Info for Prospect Heights

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 Prospect Heights

You may be interested in your other planting guides for Prospect Heights.