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.

The USDA zone info for San Francisco can be reviewed to figure out when it's a good idea to plant heliotrope.

Planting Calendar for Heliotrope

Frost tolerance for heliotrope:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since heliotrope require warm weather you need to wait until after the last frost has passed before you can plant them.

The earliest that you can plant heliotrope in San Francisco 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 heliotrope and expect a good harvest is probably September. If you wait any later than that and your heliotrope may not have a chance to fully mature. You can get started a little bit earlier by starting your heliotrope indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in San Francisco. It might get as low as 35°F during the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for San Francisco and it can change quite a bit from year to year. Since half of the time in San Francisco it frosts late in the year after January 31 be ready to protect your heliotrope if you have one of those late frosts.

USDA Zone Info for San Francisco

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in San Francisco

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