One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Washington you will be able to estimate when you can plant dahlia.

Planting Calendar for Dahlia

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

It's probably a bad 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 Washington 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. Any later than that and your dahlia may not have a chance to grow to maturity. Starting your dahlia indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Washington. It might get as low as -5°F during the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Washington and it can change quite a bit from year to year. Since half of the time in Washington you get surprised by a frost after April 15 be ready to cover your dahlia in the event of one of those late frosts.

USDA Zone Info for Washington

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 Washington

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