One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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 Issaquah can be used to determine when it's possible to plant dahlias.

Planting Calendar for Dahlias

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

You should not plant dahlias until after the last frost because they are not cold tolerant.

The earliest that you can plant dahlias in Issaquah 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 dahlias and expect a good harvest is probably August. You probably don't want to wait any later than that or else your dahlias may not have a chance to really do well. You can get started a little bit earlier by starting your dahlias indoors.

Last Frost Date

On average all chance of frost has passed is on March 15 in Issaquah. It might get as low as 15°F during the coldest months of winter.

It's important to remember that USDA zone info for Issaquah is an average and the actual date of last frost will vary from year to year. Half of the time in Issaquah you get surprised by a frost after March 15 so just be sure to be ready to cover your dahlias in the event of a late frost.

USDA Zone Info for Issaquah

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 Issaquah

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