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.

In Oak Park you can estimate when it's the best time to plant cosmos by looking at the USDA zone info.

Planting Calendar for Cosmos

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

Since cosmos are barely cold tolerant you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant cosmos in Oak Park 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 cosmos and expect a good harvest is probably August. Any later than that and your cosmos may not have a chance to really do well. Starting your cosmos indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Oak Park. In the coldest months of winter you should expect an average low temperature of -10°F.

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

USDA Zone Info for Oak Park

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 Oak Park

You may be interested in your other planting guides for Oak Park.