One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. 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 figuring out when it's a good idea to plant calla lily is to examine the USDA zone info for Riverside.

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.

Since calla lily require warm weather it is important to wait until after the last frost before you can plant them.

The earliest that you can plant calla lily in Riverside 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. If you wait any later than that and your calla lily may not have a chance to fully mature. If you are starting your calla lily indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Riverside the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Riverside and it will vary from year to year. Half of the time in Riverside it frosts late in the year after February 15 so always be ready to cover your calla lily if you have one of those late frosts.

USDA Zone Info for Riverside

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 Riverside

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