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

One way of estimating when to plant portulaca is to examine the USDA zone info for Portland.

Planting Calendar for Portulaca

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

Portulaca are not cold tolerant which tells us that it's important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant portulaca in Portland 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. You probably don't want to wait any later than that or else 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 couple of weeks earlier.

Last Frost Date

On average the last frost is on March 15 in Portland. It might get as low as 15°F during the coldest months of winter.

It's important to remember that USDA zone info for Portland is an average and the actual date of last frost changes from year to year. Half of the time in Portland there is a last frost after March 15 so make sure that you are prepared to protect your portulaca in the event of a surprise late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Portland

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