One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. 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 alternaria in Washington should be figured out by referring to the USDA zone info.

Planting Calendar for Alternaria

Frost tolerance for alternaria:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since alternaria do not do well in cold weather you have to wait until after the last frost before you can plant them.

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

Last Frost Date

The average date of last frost is April 15 in Washington. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Washington is not always accurate the actual date of last frost changes from year to year. Half of the time in Washington you get surprised by a frost after April 15 so always be ready to protect your alternaria if you have a surprise 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.