When to Plant Cosmos in Chester, 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.

In Chester you can determine when it's the best time to plant cosmos by using 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 can survive in a tiny bit of cold which means that you can plant them slightly earlier in the year 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 Chester 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. You probably don't want to wait any later than that or else your cosmos may not have a chance to really do well. Starting your cosmos indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Chester. It might get as low as 5°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Chester and it can change quite a bit from year to year. Half of the time in Chester last frost occurs after April 15 so make sure that you are prepared to protect your cosmos in the event of one of those late frosts.

USDA Zone Info for Chester

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low5°F
Highest Expected Low10°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 10°F.

Plants to Grow in Chester

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