The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 possible to plant achimenes in Portland by referring to the USDA zone info.

Planting Calendar for Achimenes

Frost tolerance for achimenes:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You really shouldn't plant achimenes until after the last frost because they do not do well in cold weather.

The earliest that you can plant achimenes 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 achimenes and expect a good harvest is probably August. If you wait any later than that and your achimenes may not have a chance to really do well. If you are starting your achimenes indoors then you might be able to get away with starting them a couple of weeks earlier.

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.

Always keep in mind that USDA zone info for Portland is an average and 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 make sure that you are prepared to cover your achimenes 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.