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 best time to plant sweet williams in San Ramon should be figured out by looking at the USDA zone info.

Planting Calendar for Sweet Williams

Frost tolerance for sweet williams:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Sweet Williams are one of those plants that can tolerate a little bit of cold weather which means that you can start planting them earlier than other frost tender plants.

The earliest that you can plant sweet williams in San Ramon is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant sweet williams and expect a good harvest is probably October. You probably don't want to wait any later than that or else your sweet williams may not have a chance to fully mature. You can get started a little bit earlier by starting your sweet williams indoors.

Last Frost Date

On average the last frost is on February 15 in San Ramon. It might get as low as 25°F during the coldest months of winter.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for San Ramon and it will vary from year to year. Half of the time in San Ramon last frost occurs after February 15 so be sure to be ready to cover your sweet williams if you have a late frost.

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.