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

It's possible to figure out when you can plant diascia by looking at the USDA zone info for Portland.

Planting Calendar for Diascia

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

Since diascia do well in moderate cold you can plant them a little 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 few weeks earlier.

Last Frost Date

In Portland the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of 0°F.

Always keep in mind that USDA zone info for Portland is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Portland last frost occurs after April 15 be ready to cover your diascia in the event of a surprise late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Portland

You may be interested in your other planting guides for Portland.