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

The USDA zone info for San Ramon should be looked at to estimate when it's a good idea to plant flower-of-an-hour.

Planting Calendar for Flower-of-an-Hour

Frost tolerance for flower-of-an-hour:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Flower-of-an-Hour are barely cold tolerant which means that you can get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant flower-of-an-hour 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 flower-of-an-hour and expect a good harvest is probably September. If you wait any later than that and your flower-of-an-hour may not have a chance to grow to maturity. If you are starting your flower-of-an-hour indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Always keep in mind that USDA zone info for San Ramon is an average and the actual date of last frost changes from year to year. Since half of the time in San Ramon it frosts late in the year after February 15 be ready to protect your flower-of-an-hour if you have a surprise 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.