Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant asparagus fern in Mercer Island can be figured out by looking at the USDA zone info.

Planting Calendar for Asparagus Fern

Frost tolerance for asparagus fern:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

You can not plant asparagus fern until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant asparagus fern in Mercer Island 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 asparagus fern and expect a good harvest is probably August. Any later than that and your asparagus fern may not have a chance to fully mature. Starting your asparagus fern 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 Mercer Island. You should expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Mercer Island is an average the actual date of last frost is different every year. Half of the time in Mercer Island it frosts late in the year after March 15 so make sure that you are prepared to protect your asparagus fern in the event of 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.