One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant cosmos in Clarks Summit can be determined by checking out 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.

Cosmos are barely cold tolerant which tells us that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant cosmos in Clarks Summit 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 fully mature. If you are starting your cosmos indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Clarks Summit is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Clarks Summit it frosts late in the year after April 15 so make sure that you are prepared to cover your cosmos if you have one of those late frosts.

USDA Zone Info for Clarks Summit

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 Clarks Summit

You may be interested in your other planting guides for Clarks Summit.