One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Napa you can determine when it's the best time to plant alstromeria by using the USDA zone info.

Planting Calendar for Alstromeria

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

Alstromeria are one of those plants that can tolerate a little bit of cold weather which means that you can plant them earlier than other frost tender plants.

The earliest that you can plant alstromeria 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 alstromeria and expect a good harvest is probably October. If you wait any later than that and your alstromeria may not have a chance to grow to maturity. Starting your alstromeria indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Napa and it can change quite a bit from year to year. Since half of the time in Napa you get surprised by a frost after February 15 be ready to cover your alstromeria in the event of a 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.