The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when you can plant cosmos by referring to the USDA zone info for Plattsburgh.

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 one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant cosmos in Plattsburgh 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. You probably don't want to wait any later than that or else your cosmos may not have a chance to really do well. You can get started a few weeks earlier by starting your cosmos indoors.

Last Frost Date

The average date of last frost is April 15 in Plattsburgh. In the coldest months of winter you should expect an average low temperature of -20°F.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Plattsburgh and it changes from year to year. Half of the time in Plattsburgh there is a last frost after April 15 so make sure that you are ready to protect your cosmos if you have one of those late frosts.

USDA Zone Info for Plattsburgh

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Plattsburgh

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