One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of getting a good idea when it's a good idea to plant tritoma is to consult the USDA zone info for Mercer Island.

Planting Calendar for Tritoma

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

Tritoma can survive in pretty solid cold which means that you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant tritoma 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 tritoma and expect a good harvest is probably September. Any later than that and your tritoma may not have a chance to grow to maturity. You can get started a little bit earlier by starting your tritoma indoors.

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 changes from year to year. Half of the time in Mercer Island you get surprised by a frost after March 15 so always be ready to protect your tritoma if you have one of those late frosts.

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.