One of the first steps you take when you are figuring out 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.

One way of making a decision about when it's a good idea to plant calla lily is to consult the USDA zone info for Portola Valley.

Planting Calendar for Calla Lily

Frost tolerance for calla lily:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's not a good idea to plant calla lily until after the last frost because they are not cold tolerant.

The earliest that you can plant calla lily in Portola Valley is February. However, you really should wait until March 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. Any later than that and your calla lily may not have a chance to really do well. You can get started a few weeks earlier by starting your calla lily indoors.

Last Frost Date

The average date of last frost is January 31 in Portola Valley. You should expect an average low temperature of 30°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Portola Valley and it changes from year to year. Half of the time in Portola Valley last frost occurs after January 31 so just be sure to be ready to protect your calla lily if you have a surprise late frost.

USDA Zone Info for Portola Valley

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Portola Valley

You may be interested in your other planting guides for Portola Valley.