One of the best tools that you have as gardeners to help us estimate 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.

It's a good idea to determine when to plant calliopsis by reviewing the USDA zone info for Seattle.

Planting Calendar for Calliopsis

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

You can not plant calliopsis until after the last frost because they are not cold tolerant.

The earliest that you can plant calliopsis in Seattle 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 calliopsis and expect a good harvest is probably August. Any later than that and your calliopsis may not have a chance to really do well. You can get started a little bit earlier by starting your calliopsis indoors.

Last Frost Date

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

Since the USDA zone info for Seattle is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Seattle you get a frost after March 15 so be sure to be ready to cover your calliopsis in the event of a surprise late frost.

USDA Zone Info for Seattle

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 Seattle

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