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.

You can determine when it's the best time to plant pearl onions in Portland by referring to the USDA zone info.

Planting Calendar for Pearl onions

Frost tolerance for pearl onions:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since pearl onions are one of those plants that can tolerate a tiny bit of cold weather you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant pearl onions 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 pearl onions and expect a good harvest is probably September. Any later than that and your pearl onions may not have a chance to grow to maturity. You can get started a little bit earlier by starting your pearl onions indoors.

Last Frost Date

The average date of last frost is February 15 in Portland. You can expect an average low temperature of 25°F in the coldest months of winter.

Keep in mind that USDA zone info for Portland is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Portland there is a last frost after February 15 be ready to protect your pearl onions if you have one of those late frosts.

USDA Zone Info for Portland

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Portland

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