Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Rialto you will be able to figure out when it's the best time to plant larkspur.

Planting Calendar for Larkspur

Frost tolerance for larkspur:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since larkspur do well in cold you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant larkspur in Rialto 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 larkspur and expect a good harvest is probably October. If you wait any later than that and your larkspur may not have a chance to fully mature. You can get started a few weeks earlier by starting your larkspur indoors.

Last Frost Date

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

Always keep in mind that USDA zone info for Rialto may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Rialto last frost occurs after January 31 so be sure to be ready to protect your larkspur if you have a surprise late frost.

USDA Zone Info for Rialto

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 Rialto

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