One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant bunching onions in Washington can be determined by using the USDA zone info.

Planting Calendar for Bunching Onions

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

Since bunching onions do ok in moderate cold you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant bunching onions 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 bunching onions and expect a good harvest is probably August. If you wait any later than that and your bunching onions may not have a chance to really do well. Starting your bunching onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Washington. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Washington is just an average the actual date of last frost is different every year. Half of the time in Washington you get a frost after April 15 so make sure that you are prepared to protect your bunching onions in the event of a late frost.

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.