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.

You should be able to estimate when it's the best time to plant lemon balm by referring to the USDA zone info for San Bruno.

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 do ok in moderate cold.

The earliest that you can plant lemon balm in San Bruno 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. You probably don't want to wait any later than that or else your lemon balm may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your lemon balm indoors.

Last Frost Date

In San Bruno the average date of last frost happens on January 31. You should expect an average low temperature of 30°F in the coldest months of winter.

Since the USDA zone info for San Bruno 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 San Bruno last frost occurs after January 31 so make sure that you are ready to protect your lemon balm in the event of a surprise late frost.

USDA Zone Info for San Bruno

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in San Bruno

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