One of the first steps you take when you are getting a good idea 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.

One way of estimating when it's the best time to plant arctotis is to refer to the USDA zone info for Mercer Island.

Planting Calendar for Arctotis

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

Arctotis are moderately cold tolerant which tells us that you can get them planted earlier than plants that are more sensitive to the cold.

The earliest that you can plant arctotis 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 arctotis and expect a good harvest is probably September. Any later than that and your arctotis may not have a chance to really do well. Starting your arctotis indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Mercer Island. You can expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Mercer Island is not always accurate the actual date of last frost changes from year to year. Since half of the time in Mercer Island you get surprised by a frost after March 15 be ready to protect your arctotis 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.