Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of estimating when it's the best time to plant scallions is to check out the USDA zone info for Portland.

Planting Calendar for Scallions

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

You can plant scallions just a tiny bit earlier in the year because they are barely cold tolerant.

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

The last month that you can plant scallions and expect a good harvest is probably August. If you wait any later than that and your scallions may not have a chance to grow to maturity. Starting your scallions indoors is a great way to get them started a little bit earlier.

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.

Just be sure to remember that the actual date of last frost is an average 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 you get a frost after April 15 so always be ready to protect your scallions 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.