One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Lake Oswego should be reviewed to determine when it's possible to plant portulaca.

Planting Calendar for Portulaca

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

You can not plant portulaca until after the last frost because they are not cold tolerant.

The earliest that you can plant portulaca in Lake Oswego 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. Any later than that and your portulaca may not have a chance to grow to maturity. You can get started a little bit earlier by starting your portulaca indoors.

Last Frost Date

The average date of last frost is March 15 in Lake Oswego. It might get as low as 15°F during the coldest months of winter.

Remember that USDA zone info for Lake Oswego may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Lake Oswego there is a last frost after March 15 so just be sure to be ready to protect your portulaca in the event of a surprise late frost.

USDA Zone Info for Lake Oswego

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 Lake Oswego

You may be interested in your other planting guides for Lake Oswego.