Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Mercer Island it's a good idea to estimate when to plant streptocarpella.

Planting Calendar for Streptocarpella

Frost tolerance for streptocarpella:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since streptocarpella are not cold tolerant it is important to wait until after the last frost has passed before you can plant them.

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

Keep in mind that USDA zone info for Mercer Island is not always accurate and the actual date of last frost is different every year. Half of the time in Mercer Island it frosts late in the year after March 15 so always be ready to protect your streptocarpella 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.