One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

The USDA zone info for Portland can be looked at to determine when it's possible to plant torenia.

Planting Calendar for Torenia

Frost tolerance for torenia:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Torenia do not do well in cold weather which means that it's important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant torenia 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 torenia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your torenia may not have a chance to grow to maturity. Starting your torenia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Portland. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Portland is just an average the actual date of last frost changes from year to year. Half of the time in Portland you get a frost after April 15 so make sure that you are ready to cover your torenia in the event of a surprise 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.