One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

It's a good idea to figure out when it's a good idea to plant basil by checking out the USDA zone info for Portland.

Planting Calendar for Basil

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

You should not plant basil until after the last frost because they are not cold tolerant.

The earliest that you can plant basil 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 basil and expect a good harvest is probably August. You probably don't want to wait any later than that or else your basil may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your basil indoors.

Last Frost Date

The average date of last frost is April 15 in Portland. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Portland and it will vary from year to year. Half of the time in Portland last frost occurs after April 15 so be sure to be ready to cover your basil in the event of a late frost.

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.