The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 Portland should be looked at to determine when it's a good idea to plant borage.

Planting Calendar for Borage

Frost tolerance for borage:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Borage tend to make it in moderate cold which means that you can plant them a little earlier in the year than other plants that might not handle the cold.

The earliest that you can plant borage 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 borage and expect a good harvest is probably September. Any later than that and your borage may not have a chance to grow to maturity. If you are starting your borage indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Portland. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Portland is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Portland it frosts late in the year after April 15 so just be sure to be ready to cover your borage if you have 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.