When to Plant Alstromeria in San Ramon, CA

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.

The USDA zone info for San Ramon should be used to estimate when you can plant alstromeria.


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 plants that might not handle the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant alstromeria
Possibly ok, but a risky time to plant alstromeria
Probably not a good time to plant alstromeria

The earliest that you can plant alstromeria in San Ramon 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 fully mature. You can get started a couple of weeks earlier by starting your alstromeria indoors.

Last Frost Date

The average date of last frost is February 15 in San Ramon. In the coldest months of winter you can expect an average low temperature of 25°F.

Keep in mind that USDA zone info for San Ramon is an average and the actual date of last frost is different every year. Since half of the time in San Ramon you get surprised by a frost after February 15 be ready to protect your alstromeria in the event of a late frost.

USDA Zone Info for San Ramon

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 Low25°F
Highest Expected Low30°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 San Ramon

You may be interested in your other planting guides for San Ramon.