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.

One way of estimating when it's a good idea to plant calendula is to look at the USDA zone info for San Bruno.

Planting Calendar for Calendula

Frost tolerance for calendula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Calendula are moderately cold tolerant which means that you can plant them earlier than more sensitive plants.

The earliest that you can plant calendula in San Bruno 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 calendula and expect a good harvest is probably October. If you wait any later than that and your calendula may not have a chance to grow to maturity. You can get started a little bit earlier by starting your calendula indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in San Bruno. It might get as low as 30°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for San Bruno and it will vary from year to year. Since half of the time in San Bruno there is a last frost after January 31 be ready to protect your calendula in the event of a surprise late frost.

USDA Zone Info for San Bruno

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 San Bruno

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