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 earliest that you can plant cosmos in Windsor should be figured out by referring to 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 do ok in moderate cold which means that you can plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant cosmos in Windsor 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 fully mature. You can get started a little bit earlier by starting your cosmos indoors.

Last Frost Date

The average date of last frost is April 15 in Windsor. It might get as low as -15°F during the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Windsor and it changes from year to year. Since half of the time in Windsor last frost occurs after April 15 be ready to cover your cosmos if you have a late frost.

USDA Zone Info for Windsor

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Windsor

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