One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when to plant cosmos is to check out the USDA zone info for Pleasant Hill.

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 do ok in a tiny bit of cold which tells us that you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant cosmos in Pleasant Hill 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 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

In Pleasant Hill the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Pleasant Hill and it changes from year to year. Half of the time in Pleasant Hill last frost occurs after April 15 so always be ready to cover your cosmos if you have a surprise late frost.

USDA Zone Info for Pleasant Hill

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 Pleasant Hill

You may be interested in your other planting guides for Pleasant Hill.