One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to figure out when you can plant lithospermum by looking at the USDA zone info for San Diego.

Planting Calendar for Lithospermum

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

It's not a good idea to plant lithospermum until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant lithospermum in San Diego 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

In San Diego the average date of last frost happens on January 31. You can expect an average low temperature of 35°F in the coldest months of winter.

Since the USDA zone info for San Diego is an average the actual date of last frost will vary from year to year. Since half of the time in San Diego you get a frost after January 31 be ready to cover your lithospermum in the event of a surprise late frost.

USDA Zone Info for San Diego

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 Diego

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