The USDA Zone info is a great tool for gardeners to help us determine 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.

One way of getting a good idea when to plant cosmos is to examine the USDA zone info for Bellevue.

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 tend to make it in some cold which means that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant cosmos in Bellevue 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. If you wait 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

The average date of last frost is April 15 in Bellevue. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Bellevue is an average the actual date of last frost is different every year. Half of the time in Bellevue you get surprised by a frost after April 15 so just be sure to be ready to cover your cosmos if you have a surprise late frost.

USDA Zone Info for Bellevue

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 Bellevue

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