One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of figuring out when it's possible to plant leeks is to check out the USDA zone info for Bourbonnais.

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 quite a bit of cold which tells us that you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant leeks in Bourbonnais 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 fully mature. Starting your leeks indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Bourbonnais. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Bourbonnais and it is different every year. Half of the time in Bourbonnais you get surprised by a frost after April 15 so make sure that you are ready to protect your leeks if you have a late frost.

USDA Zone Info for Bourbonnais

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 Bourbonnais

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