One of the best tools that you have as gardeners to help us figure out 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.

It's possible to figure out when it's the best time to plant cosmos by looking at the USDA zone info for Niagara Falls.

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 Niagara Falls 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. You can get started a few weeks earlier by starting your cosmos indoors.

Last Frost Date

In Niagara Falls the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Niagara Falls is not always accurate the actual date of last frost is different every year. Since half of the time in Niagara Falls it frosts late in the year after April 15 be ready to protect your cosmos in the event of one of those late frosts.

USDA Zone Info for Niagara Falls

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 Niagara Falls

You may be interested in your other planting guides for Niagara Falls.