The USDA Zone info is a great tool for gardeners to help us determine 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 USDA zone info for Napa should be used to estimate when to plant hosta.

Planting Calendar for Hosta

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

Hosta can survive in mild cold which tells us that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant hosta 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 hosta and expect a good harvest is probably October. If you wait any later than that and your hosta may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your hosta indoors.

Last Frost Date

On average all chance of frost has passed is on February 15 in Napa. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Napa is just an average the actual date of last frost is different every year. Half of the time in Napa there is a last frost after February 15 so just be sure to be ready to cover your hosta in the event of a surprise late frost.

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.