One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of figuring out when to plant calibrachoa is to consult the USDA zone info for Portland.

Planting Calendar for Calibrachoa

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

Calibrachoa tend to make it in mild cold which means that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant calibrachoa 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 calibrachoa and expect a good harvest is probably August. You probably don't want to wait any later than that or else your calibrachoa may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your calibrachoa indoors.

Last Frost Date

In Portland the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Keep in mind that USDA zone info for Portland is not always accurate and 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 always be ready to cover your calibrachoa if you have 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.