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

One way of estimating when it's possible to plant lemon balm is to examine the USDA zone info for San Ramon.

Planting Calendar for Lemon balm

Frost tolerance for lemon balm:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant lemon balm slightly earlier in the year because they are barely cold tolerant.

The earliest that you can plant lemon balm in San Ramon 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 lemon balm and expect a good harvest is probably September. If you wait any later than that and your lemon balm may not have a chance to fully mature. If you are starting your lemon balm indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In San Ramon the average date of last frost happens on February 15. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for San Ramon is just an average the actual date of last frost is different every year. Half of the time in San Ramon last frost occurs after February 15 so make sure that you are prepared to protect your lemon balm if you have one of those late frosts.

USDA Zone Info for San Ramon

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 San Ramon

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