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

You can figure out when it's the best time to plant twinspur in Mercer Island by looking at the USDA zone info.

Planting Calendar for Twinspur

Frost tolerance for twinspur:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Twinspur are one of those plants that can tolerate a little bit of cold weather which tells us that you can plant them a little bit earlier than other plants that might not handle the cold.

The earliest that you can plant twinspur 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 twinspur and expect a good harvest is probably September. Any later than that and your twinspur may not have a chance to fully mature. If you are starting your twinspur indoors then you might be able to get away with starting them a few weeks 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.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Mercer Island and it can change quite a bit 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 cover your twinspur 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.