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

The USDA zone info for Bothell can be read to figure out when you can plant columbine.

Planting Calendar for Columbine

Frost tolerance for columbine:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant columbine just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant columbine in Bothell is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant columbine and expect a good harvest is probably September. If you wait any later than that and your columbine may not have a chance to fully mature. Starting your columbine indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Bothell. In the coldest months of winter you should expect an average low temperature of 15°F.

Since the USDA zone info for Bothell is just an average the actual date of last frost will vary from year to year. Half of the time in Bothell it frosts late in the year after March 15 so make sure that you are prepared to cover your columbine in the event of a late frost.

USDA Zone Info for Bothell

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 Bothell

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