The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant lemon balm in Rialto should be determined by using the USDA zone info.

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.

Since lemon balm are one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than more sensitive plants.

The earliest that you can plant lemon balm in Rialto 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 couple of weeks earlier.

Last Frost Date

In Rialto the average date of last frost happens on January 31. In the coldest months of winter you should expect an average low temperature of 30°F.

Since the USDA zone info for Rialto is an average the actual date of last frost changes from year to year. Since half of the time in Rialto last frost occurs after January 31 be ready to cover your lemon balm if you have a late frost.

USDA Zone Info for Rialto

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 Rialto

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