The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Grafton you should be able to estimate when it's possible to 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 do well in very little cold which tells us that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant cosmos in Grafton 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 grow to maturity. Starting your cosmos indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Remember that USDA zone info for Grafton is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Grafton last frost occurs after April 15 so just be sure to be ready to protect your cosmos if you have a late frost.

USDA Zone Info for Grafton

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 Grafton

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