Before planting it is a good idea to find your USDA Zone info to estimate your garden 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 can be looked at to figure out when it's possible to plant snow-in summer.

Planting Calendar for Snow-in Summer

Frost tolerance for snow-in summer:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Snow-in Summer tend to make it in mild cold which tells us that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant snow-in summer 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 snow-in summer and expect a good harvest is probably October. If you wait any later than that and your snow-in summer may not have a chance to really do well. If you are starting your snow-in summer 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. It might get as low as 25°F during the coldest months of winter.

It's important to remember that USDA zone info for Napa is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Napa last frost occurs after February 15 so make sure that you are prepared to protect your snow-in summer 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.