The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to figure out when it's possible to plant iceberg lettuce by reviewing the USDA zone info for Mercer Island.

Planting Calendar for Iceberg lettuce

Frost tolerance for iceberg lettuce:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Iceberg lettuce do well in very little cold which tells us that you can plant them slightly earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant iceberg lettuce in Mercer Island is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant iceberg lettuce and expect a good harvest is probably August. You probably don't want to wait any later than that or else your iceberg lettuce may not have a chance to grow to maturity. If you are starting your iceberg lettuce indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Mercer Island and it changes from year to year. Half of the time in Mercer Island there is a last frost after March 15 so just be sure to be ready to protect your iceberg lettuce in the event of a surprise 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.