Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of getting a good idea when it's possible to plant lithospermum is to use the USDA zone info for Atherton.

Planting Calendar for Lithospermum

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

Since lithospermum require warm weather you really should wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant lithospermum in Atherton is March. However, you really should wait until April 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. If you wait any later than that and your lithospermum may not have a chance to fully mature. If you are starting your lithospermum indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Atherton. In the coldest months of winter you can expect an average low temperature of 25°F.

Since the USDA zone info for Atherton may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Atherton there is a last frost after February 15 so just be sure to be ready to protect your lithospermum if you have a late frost.

USDA Zone Info for Atherton

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 Atherton

You may be interested in your other planting guides for Atherton.