One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. 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 Tualatin should be determined by using the USDA zone info.

Planting Calendar for Portulaca

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

It's probably a bad idea to plant portulaca until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant portulaca in Tualatin 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 really do well. Starting your portulaca indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Always keep in mind that USDA zone info for Tualatin is just an average and the actual date of last frost will vary from year to year. Since half of the time in Tualatin you get surprised by a frost after March 15 be ready to cover your portulaca in the event of one of those late frosts.

USDA Zone Info for Tualatin

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 Tualatin

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