One of the first steps you take when you are determining 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.

By looking at the USDA zone info for Ithaca you will be able to figure out when you can plant cosmos.

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 plants that are more sensitive to the cold.

The earliest that you can plant cosmos in Ithaca 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. If you wait any later than that and your cosmos may not have a chance to really do well. You can get started a little bit earlier by starting your cosmos indoors.

Last Frost Date

In Ithaca 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 Ithaca is just an average the actual date of last frost will vary from year to year. Half of the time in Ithaca you get surprised by a frost after April 15 so just be sure to be ready to cover your cosmos in the event of one of those late frosts.

USDA Zone Info for Ithaca

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 Ithaca

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