Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Stillwater it's a good idea to figure out when to plant zinnia.

Planting Calendar for Zinnia

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

It's probably a bad idea to plant zinnia until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant zinnia in Stillwater 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 really do well. Starting your zinnia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Stillwater. You can expect an average low temperature of -25°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Stillwater is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Stillwater it frosts late in the year after May 15 so just be sure to be ready to protect your zinnia in the event of a surprise late frost.

USDA Zone Info for Stillwater

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 Stillwater

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