When to Plant Cosmos in Mechanicsburg, PA

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.

You will be able to estimate when you can plant cosmos by checking out the USDA zone info for Mechanicsburg.


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 plant them slightly earlier than other frost tender plants.

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 Mechanicsburg 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 couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Mechanicsburg. In the coldest months of winter you can expect an average low temperature of 0°F.

Since the USDA zone info for Mechanicsburg is an average the actual date of last frost changes from year to year. Half of the time in Mechanicsburg you get a frost after April 15 so make sure that you are ready to cover your cosmos if you have a late frost.

USDA Zone Info for Mechanicsburg

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low0°F
Highest Expected Low5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Mechanicsburg

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