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 USDA zone info for Pullman can be reffered to in order to figure out when to plant trailing portulaca.

Planting Calendar for Trailing Portulaca

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

It's not a good idea to plant trailing portulaca until after the last frost when the weather gets warmer because they require warm weather.

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

Last Frost Date

In Pullman the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Pullman is just an average the actual date of last frost will vary from year to year. Since half of the time in Pullman last frost occurs after April 15 be ready to cover your trailing portulaca if you have a surprise late frost.

USDA Zone Info for Pullman

Here is the info for USDA Zone 6b.

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

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

Plants to Grow in Pullman

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