Before planting it is a good idea to find your USDA Zone info to determine 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.

A common way of getting a good idea when to plant alstromeria is to use the USDA zone info for Petaluma.

Planting Calendar for Alstromeria

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

Alstromeria can survive in a little bit of cold which means that you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant alstromeria in Petaluma 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. Any later than that and your alstromeria may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your alstromeria indoors.

Last Frost Date

In Petaluma 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.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Petaluma and it changes from year to year. Since half of the time in Petaluma there is a last frost after February 15 be ready to cover your alstromeria if you have one of those late frosts.

USDA Zone Info for Petaluma

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 Petaluma

You may be interested in your other planting guides for Petaluma.