One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Mercer Island you can estimate when to plant coleus by checking out the USDA zone info.

Planting Calendar for Coleus

Frost tolerance for coleus:	Not tolerant of frost.
When to plant:	After the last frost.

It's probably not a good idea to plant coleus until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant coleus 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 coleus and expect a good harvest is probably August. Any later than that and your coleus may not have a chance to grow to maturity. If you are starting your coleus indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Mercer Island. It might get as low as 15°F during 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. Half of the time in Mercer Island you get surprised by a frost after March 15 so make sure that you are prepared to protect your coleus 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.