The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant violas in Napa can be figured out by referring to the USDA zone info.

Planting Calendar for Violas

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

Since violas do well in cold you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant violas in Napa is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant violas and expect a good harvest is probably October. If you wait any later than that and your violas may not have a chance to grow to maturity. If you are starting your violas indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Napa and it changes from year to year. Since half of the time in Napa you get a frost after February 15 be ready to cover your violas 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.