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

In Oregon you can determine when to plant dahlia by looking at the USDA zone info.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably not a good idea to plant dahlia until after all chance of frost has passed because they require warm weather.

The earliest that you can plant dahlia in Oregon 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 dahlia and expect a good harvest is probably August. If you wait any later than that and your dahlia may not have a chance to really do well. Starting your dahlia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Oregon the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -5°F.

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 Oregon and it will vary from year to year. Since half of the time in Oregon last frost occurs after April 15 be ready to cover your dahlia if you have one of those late frosts.

USDA Zone Info for Oregon

Here is the info for USDA Zone 6b.

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

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

Plants to Grow in Oregon

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