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.

The first opportunity to plant snow-in summer in Portland can be estimated by looking at the USDA zone info.

Planting Calendar for Snow-in Summer

Frost tolerance for snow-in summer:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since snow-in summer are one of those plants that can tolerate a little 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 snow-in summer 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 snow-in summer and expect a good harvest is probably September. If you wait any later than that and your snow-in summer may not have a chance to grow to maturity. If you are starting your snow-in summer indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Portland. It might get as low as -15°F during the coldest months of winter.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Portland and it is different every year. Half of the time in Portland last frost occurs after April 15 so always be ready to cover your snow-in summer 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.