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

The USDA zone info for Napa can be looked at to figure out when it's possible to plant purple bell vines.

Planting Calendar for Purple Bell Vines

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

Purple Bell Vines can survive in some cold which tells us that you can plant them just a tiny bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant purple bell vines 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 bell vines and expect a good harvest is probably September. You probably don't want to wait any later than that or else your purple bell vines may not have a chance to grow to maturity. If you are starting your purple bell vines indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Always keep in mind that USDA zone info for Napa is an average and the actual date of last frost will vary from year to year. Half of the time in Napa you get surprised by a frost after February 15 so make sure that you are prepared to cover your purple bell vines if you have 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.