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

A common way of making a decision about when it's a good idea to plant sweet williams is to refer to the USDA zone info for Walla Walla.

Planting Calendar for Sweet Williams

Frost tolerance for sweet williams:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Sweet Williams do well in moderate cold which means that you can plant them a little bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant sweet williams in Walla Walla is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant sweet williams and expect a good harvest is probably September. Any later than that and your sweet williams may not have a chance to really do well. You can get started a few weeks earlier by starting your sweet williams indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Walla Walla. In the coldest months of winter you should expect an average low temperature of 0°F.

Since the USDA zone info for Walla Walla may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Walla Walla last frost occurs after April 15 so make sure that you are ready to protect your sweet williams in the event of one of those late frosts.

USDA Zone Info for Walla Walla

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Walla Walla

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