One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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 way of determining when you can plant calendula is to look at the USDA zone info for Redwood City.

Planting Calendar for Calendula

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

Calendula can survive in a little bit of cold which tells us that you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant calendula in Redwood City 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. Any later than that and your calendula may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your calendula indoors.

Last Frost Date

On average all chance of frost has passed is on February 15 in Redwood City. In the coldest months of winter you can expect an average low temperature of 25°F.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Redwood City and it will vary from year to year. Half of the time in Redwood City it frosts late in the year after February 15 so make sure that you are ready to protect your calendula if you have a late frost.

USDA Zone Info for Redwood City

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 Redwood City

You may be interested in your other planting guides for Redwood City.