One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when it's a good idea to plant zinnia by reviewing the USDA zone info for Green River.

Planting Calendar for Zinnia

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

Zinnia do not do well in cold weather which means that it is important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant zinnia in Green River is May. However, you really should wait until June 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. If you wait any later than that and your zinnia may not have a chance to fully mature. Starting your zinnia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Green River the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Green River is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Green River you get a frost after May 15 be ready to cover your zinnia if you have a late frost.

USDA Zone Info for Green River

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Green River

You may be interested in your other planting guides for Green River.