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

A way of getting a good idea when to plant zinnia is to refer to the USDA zone info for Chelsea.

Planting Calendar for Zinnia

Frost tolerance for zinnia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since zinnia require warm weather you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant zinnia in Chelsea is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant zinnia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your zinnia may not have a chance to really do well. If you are starting your zinnia 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 when the weather gets warmer is on April 15 in Chelsea. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Chelsea is just an average the actual date of last frost changes from year to year. Half of the time in Chelsea last frost occurs after April 15 so make sure that you are ready to protect your zinnia if you have a surprise late frost.

USDA Zone Info for Chelsea

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 Chelsea

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