One of the best tools that you have as gardeners to help us estimate 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 first chance to plant asparagus in Portland can be estimated by reviewing the USDA zone info.

Planting Calendar for Asparagus

Frost tolerance for asparagus:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant asparagus earlier in the year because they are very cold tolerant.

The earliest that you can plant asparagus in Portland is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant asparagus and expect a good harvest is probably September. You probably don't want to wait any later than that or else your asparagus may not have a chance to fully mature. If you are starting your asparagus indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Keep in mind that USDA zone info for Portland may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Portland you get a frost after April 15 so make sure that you are ready to cover your asparagus if you have 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.