One of the first steps you take when you are figuring out your gardening schedule is find your 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 way of figuring out when you can plant rosemary is to look at the USDA zone info for Seattle.

Planting Calendar for Rosemary

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

Since rosemary do well in cold you can plant them much earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant rosemary in Seattle 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 rosemary and expect a good harvest is probably September. You probably don't want to wait any later than that or else your rosemary may not have a chance to grow to maturity. Starting your rosemary indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Seattle the average date of last frost happens on March 15. It might get as low as 15°F during the coldest months of winter.

Always keep in mind that USDA zone info for Seattle is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Seattle you get a frost after March 15 so always be ready to cover your rosemary in the event of one of those late frosts.

USDA Zone Info for Seattle

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 Seattle

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