Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to figure out when to plant cosmos by referring to the USDA zone info for Hayden.

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 start planting them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant cosmos in Hayden 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 little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Hayden. In the coldest months of winter you can expect an average low temperature of -5°F.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Hayden and it can change quite a bit from year to year. Since half of the time in Hayden there is a last frost after April 15 be ready to cover your cosmos in the event of a surprise late frost.

USDA Zone Info for Hayden

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Hayden

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