The USDA Zone info is a great tool for gardeners to help us determine 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.

The first opportunity to plant lithospermum in San Francisco can be estimated by referring to the USDA zone info.

Planting Calendar for Lithospermum

Frost tolerance for lithospermum:	Not tolerant of frost.
When to plant:	After the last frost.

Since lithospermum are not cold tolerant you have to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant lithospermum 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 lithospermum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your lithospermum may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your lithospermum indoors.

Last Frost Date

The average date of last frost is January 31 in San Francisco. In the coldest months of winter you can expect an average low temperature of 35°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 San Francisco and it can change quite a bit from year to year. Since half of the time in San Francisco you get surprised by a frost after January 31 be ready to cover your lithospermum in the event of a late frost.

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.