The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. 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 Mercer Island should be looked at to estimate when it's a good idea to plant garlic.

Planting Calendar for Garlic

Frost tolerance for garlic:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Garlic are very cold tolerant which means that you can start planting them much earlier than more sensitive plants.

The earliest that you can plant garlic 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 garlic and expect a good harvest is probably September. Any later than that and your garlic may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your garlic indoors.

Last Frost Date

The average date of last frost is March 15 in Mercer Island. You can expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Mercer Island is just an average the actual date of last frost will vary from year to year. Since half of the time in Mercer Island it frosts late in the year after March 15 be ready to cover your garlic 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.