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.

By looking at the USDA zone info for Sterling you will be able to determine when it's possible to plant cosmos.

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 are one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant cosmos in Sterling 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 really do well. If you are starting your cosmos indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Sterling may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Sterling you get a frost after April 15 so make sure that you are ready to protect your cosmos if you have a surprise late frost.

USDA Zone Info for Sterling

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 Sterling

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