Before planting it is a good idea to find your USDA Zone info to figure out your garden 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 you can plant trifolium is to consult the USDA zone info for Chicago.

Planting Calendar for Trifolium

Frost tolerance for trifolium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant trifolium slightly earlier in the year because they are barely cold tolerant.

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

Last Frost Date

In Chicago the average date of last frost happens on April 15. You should expect an average low temperature of -10°F in the coldest months of winter.

Remember that USDA zone info for Chicago is not always accurate and the actual date of last frost changes from year to year. Half of the time in Chicago there is a last frost after April 15 so always be ready to cover your trifolium in the event of a surprise late frost.

USDA Zone Info for Chicago

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Chicago

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