One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to determine when you can plant petunias by looking at the USDA zone info for Washington.

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.

Petunias tend to make it in very little cold which means that you can plant them just a tiny bit earlier in the year than more sensitive plants.

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. Starting your petunias indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Washington the average date of last frost happens on March 15. In the coldest months of winter you can expect an average low temperature of 10°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Washington and it is different every year. Half of the time in Washington there is a last frost after March 15 so just be sure to 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 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

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

Plants to Grow in Washington

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