When to Plant Cosmos in Lake Stevens, WA

Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant cosmos in Lake Stevens 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 are barely cold tolerant which means that you can start planting them slightly earlier than plants that are more sensitive to the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant cosmos
Possibly ok, but a risky time to plant cosmos
Probably not a good time to plant cosmos

The earliest that you can plant cosmos in Lake Stevens 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 fully mature. Starting your cosmos indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on March 15 in Lake Stevens. You should expect an average low temperature of 15°F in the coldest months of winter.

It's important to remember that USDA zone info for Lake Stevens is just an average and the actual date of last frost changes from year to year. Since half of the time in Lake Stevens you get a frost after March 15 be ready to cover your cosmos if you have a late frost.

USDA Zone Info for Lake Stevens

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)March 15
Average Date of First Frost (fall)November 15
Lowest Expected Low15°F
Highest Expected Low20°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 20°F.

Plants to Grow in Lake Stevens

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