The USDA Zone info is a great tool for gardeners to help us figure out your gardening 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 looked at to estimate when it's possible to plant calla lily.

Planting Calendar for Calla Lily

Frost tolerance for calla lily:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Calla Lily do not do well in cold weather which tells us that you must wait until it warms up after the last frost before you can plant them.

The earliest that you can plant calla lily in San Ramon 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 calla lily and expect a good harvest is probably September. You probably don't want to wait any later than that or else your calla lily may not have a chance to really do well. You can get started a little bit earlier by starting your calla lily indoors.

Last Frost Date

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

Just be sure to remember 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 San Ramon and it changes from year to year. Half of the time in San Ramon there is a last frost after February 15 so always be ready to protect your calla lily if you have a surprise 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 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 San Ramon

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