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

In Napa you can estimate when to plant purple coneflower by referring to the USDA zone info.

Planting Calendar for Purple Coneflower

Frost tolerance for purple coneflower:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since purple coneflower are barely cold tolerant you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant purple coneflower in Napa 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 purple coneflower and expect a good harvest is probably September. Any later than that and your purple coneflower may not have a chance to fully mature. You can get started a few weeks earlier by starting your purple coneflower indoors.

Last Frost Date

In Napa the average date of last frost happens on February 15. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Napa is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Napa it frosts late in the year after February 15 be ready to protect your purple coneflower in the event of one of those late frosts.

USDA Zone Info for Napa

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Napa

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