Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to figure out when to plant cosmos by referring to the USDA zone info for Glenwood Springs.

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.

You can plant cosmos slightly earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant cosmos in Glenwood Springs 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. 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 Glenwood Springs. You should expect an average low temperature of -10°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Glenwood Springs and it is different every year. Since half of the time in Glenwood Springs you get surprised by a frost after April 15 be ready to cover your cosmos in the event of a late frost.

USDA Zone Info for Glenwood Springs

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 Glenwood Springs

You may be interested in your other planting guides for Glenwood Springs.