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

One way of making a decision about when it's a good idea to plant leeks is to refer to the USDA zone info for Mercer Island.

Planting Calendar for Leeks

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

Since leeks are very cold tolerant you can plant them quite a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant leeks 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 leeks and expect a good harvest is probably September. You probably don't want to wait any later than that or else your leeks may not have a chance to fully mature. Starting your leeks indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Mercer Island the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 15°F.

Since the USDA zone info for Mercer Island is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Mercer Island last frost occurs after March 15 so make sure that you are ready to protect your leeks 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.