One of the first steps you take when you are making a decision about 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.

The USDA zone info for Troutdale can be reffered to in order to figure out when it's possible to plant dahlia.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After the last frost.

You really shouldn't plant dahlia until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant dahlia in Troutdale 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 fully mature. Starting your dahlia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Troutdale. It might get as low as 15°F during the coldest months of winter.

Since the USDA zone info for Troutdale is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Troutdale there is a last frost after March 15 be ready to cover your dahlia in the event of a late frost.

USDA Zone Info for Troutdale

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Troutdale

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