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

By looking at the USDA zone info for Napa it's possible to determine when it's a good idea to plant trailing portulaca.

Planting Calendar for Trailing Portulaca

Frost tolerance for trailing portulaca:	Not tolerant of frost.
When to plant:	After the last frost.

Trailing Portulaca are not cold tolerant which tells us that you need to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant trailing portulaca in Napa is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant trailing portulaca and expect a good harvest is probably September. You probably don't want to wait any later than that or else your trailing portulaca may not have a chance to grow to maturity. If you are starting your trailing portulaca 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. In the coldest months of winter you should expect an average low temperature of 25°F.

Just be sure to remember that USDA zone info for Napa is an average and the actual date of last frost is different every year. Half of the time in Napa last frost occurs after February 15 so just be sure to be ready to cover your trailing portulaca 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.