Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant diascia in Portland should be estimated by looking at the USDA zone info.

Planting Calendar for Diascia

Frost tolerance for diascia:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Diascia can survive in moderate cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant diascia 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 diascia and expect a good harvest is probably September. If you wait any later than that and your diascia may not have a chance to grow to maturity. If you are starting your diascia 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.

Remember that USDA zone info for Portland is an average and the actual date of last frost changes from year to year. Half of the time in Portland last frost occurs after April 15 so always be ready to cover your diascia 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.