The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant portulaca in Washington should be determined by referring to the USDA zone info.

Planting Calendar for Portulaca

Frost tolerance for portulaca:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's a bad idea to plant portulaca until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant portulaca 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 portulaca and expect a good harvest is probably August. If you wait any later than that and your portulaca may not have a chance to grow to maturity. If you are starting your portulaca indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Always keep in mind that USDA zone info for Washington may not be accurate from year to year and the actual date of last frost changes from year to year. Since half of the time in Washington you get a frost after April 15 be ready to protect your portulaca in the event of 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.