The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In River Forest you can figure out when it's possible to plant calendula by checking out the USDA zone info.

Planting Calendar for Calendula

Frost tolerance for calendula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Calendula do well in some cold which means that you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant calendula in River Forest 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 calendula and expect a good harvest is probably September. If you wait any later than that and your calendula may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your calendula indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in River Forest. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for River Forest may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in River Forest you get surprised by a frost after April 15 be ready to cover your calendula in the event of one of those late frosts.

USDA Zone Info for River Forest

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 River Forest

You may be interested in your other planting guides for River Forest.