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.

The first chance to plant zinnia in Washington should be estimated by checking out the USDA zone info.

Planting Calendar for Zinnia

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

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

The earliest that you can plant zinnia in Washington 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. Any later than that and your zinnia may not have a chance to grow to maturity. You can get started a little bit earlier by starting your zinnia indoors.

Last Frost Date

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

Remember that USDA zone info for Washington may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Washington last frost occurs after April 15 be ready to protect your zinnia in the event of one of those late frosts.

USDA Zone Info for Washington

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Washington

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