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 Umatilla you can estimate when you can plant zinnia by looking at the USDA zone info.

Planting Calendar for Zinnia

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

Zinnia require warm weather which tells us that it's important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant zinnia in Umatilla 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. 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 little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Umatilla. In the coldest months of winter you can expect an average low temperature of 5°F.

Since the USDA zone info for Umatilla is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Umatilla you get a frost after April 15 be ready to cover your zinnia in the event of one of those late frosts.

USDA Zone Info for Umatilla

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 Low	5°F
Highest Expected Low	10°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 Umatilla

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