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.

In Umatilla you can figure out when it's possible to plant trailing portulaca by using the USDA zone info.

Planting Calendar for Trailing Portulaca

Frost tolerance for trailing portulaca:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Trailing Portulaca do not do well in cold weather which means that it's necessary to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant trailing portulaca in Umatilla 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. You probably don't want to wait any later than that or else your trailing portulaca may not have a chance to really do well. Starting your trailing portulaca indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Umatilla. In the coldest months of winter you should expect an average low temperature of 5°F.

Since the USDA zone info for Umatilla may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Umatilla last frost occurs after April 15 be ready to cover your trailing portulaca if you have a late frost.

USDA Zone Info for Umatilla

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Umatilla

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