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

You should be able to figure out when it's possible to plant osteospermum by using the USDA zone info for Sammamish.

Planting Calendar for Osteospermum

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

Since osteospermum are moderately cold tolerant you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

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

Last Frost Date

On average all chance of frost has passed is on March 15 in Sammamish. In the coldest months of winter you should expect an average low temperature of 15°F.

Since the USDA zone info for Sammamish is not always accurate the actual date of last frost will vary from year to year. Half of the time in Sammamish it frosts late in the year after March 15 so make sure that you are ready to cover your osteospermum in the event of one of those late frosts.

USDA Zone Info for Sammamish

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 Sammamish

You may be interested in your other planting guides for Sammamish.