One of the first steps you take when you are determining your gardening schedule is find your 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 Portland you can figure out when to plant asparagus lettuce by referring to the USDA zone info.

Planting Calendar for Asparagus lettuce

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

You can not plant asparagus lettuce until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant asparagus lettuce 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 asparagus lettuce and expect a good harvest is probably August. You probably don't want to wait any later than that or else your asparagus lettuce may not have a chance to grow to maturity. You can get started a little bit earlier by starting your asparagus lettuce indoors.

Last Frost Date

In Portland the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Portland is not always accurate the actual date of last frost changes from year to year. Since half of the time in Portland last frost occurs after April 15 be ready to cover your asparagus lettuce in the event of one of those late frosts.

USDA Zone Info for Portland

Here is the info for USDA Zone 5b.

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

Plants to Grow in Portland

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