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

The USDA zone info for Washington should be looked at to figure out when it's possible to plant petunias.

Planting Calendar for Petunias

Frost tolerance for petunias:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant petunias slightly earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

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

The last month that you can plant petunias and expect a good harvest is probably August. If you wait any later than that and your petunias may not have a chance to really do well. You can get started a little bit earlier by starting your petunias indoors.

Last Frost Date

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

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Washington and it is different every year. Since half of the time in Washington it frosts late in the year after April 15 be ready to protect your petunias in the event of a late frost.

USDA Zone Info for Washington

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 Washington

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