The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Napa you should be able to figure out when to plant impatiens.

Planting Calendar for Impatiens

Frost tolerance for impatiens:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably not a good idea to plant impatiens until after the last frost has passed because they require warm weather.

The earliest that you can plant impatiens 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 impatiens and expect a good harvest is probably September. You probably don't want to wait any later than that or else your impatiens may not have a chance to really do well. If you are starting your impatiens indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Just be sure 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 it frosts late in the year after February 15 so always be ready to cover your impatiens 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.