Before planting it is a good idea to find your USDA Zone info to determine 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.

The first opportunity to plant cosmos in Liberty Lake can be figured out by referring to 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.

Cosmos tend to make it in some cold which means that 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 Liberty Lake 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. 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

The average date of last frost is April 15 in Liberty Lake. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Liberty Lake may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Liberty Lake you get surprised by a frost after April 15 be ready to cover your cosmos if you have a surprise late frost.

USDA Zone Info for Liberty Lake

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 Liberty Lake

You may be interested in your other planting guides for Liberty Lake.