One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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 looking at the USDA zone info for Mercer Island you should be able to determine when it's a good idea to plant bishop's weed.

Planting Calendar for Bishop's Weed

Frost tolerance for bishop's weed:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant bishop's weed a lot earlier in the year because they are very cold tolerant.

The earliest that you can plant bishop's weed in Mercer Island 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 bishop's weed and expect a good harvest is probably September. Any later than that and your bishop's weed may not have a chance to grow to maturity. Starting your bishop's weed indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Mercer Island. You can expect an average low temperature of 15°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Mercer Island and it is different every year. Since half of the time in Mercer Island last frost occurs after March 15 be ready to cover your bishop's weed if you have a late frost.

USDA Zone Info for Mercer Island

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 Mercer Island

You may be interested in your other planting guides for Mercer Island.