One of the first steps you take when you are figuring out 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.

In Portland you can determine when you can plant violas by reviewing the USDA zone info.

Planting Calendar for Violas

Frost tolerance for violas:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since violas do well in cold you can plant them earlier in the year than more sensitive plants.

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

The last month that you can plant violas and expect a good harvest is probably October. You probably don't want to wait any later than that or else your violas may not have a chance to fully mature. Starting your violas indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in Portland. It might get as low as 25°F during the coldest months of winter.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Portland and it will vary from year to year. Since half of the time in Portland last frost occurs after February 15 be ready to cover your violas if you have a late frost.

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.