The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant cosmos in Bellevue should be estimated by reviewing 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.

Since cosmos do ok in moderate cold 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. You probably don't want to wait any later than that or else your cosmos may not have a chance to really do well. If you are starting your cosmos indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Keep in mind that USDA zone info for Bellevue is an average and the actual date of last frost changes from year to year. Half of the time in Bellevue you get surprised by a frost after April 15 so make sure that you are ready to protect your cosmos in the event of a late frost.

USDA Zone Info for Bellevue

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 Bellevue

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