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

One way of figuring out when you can plant nierembergia is to examine the USDA zone info for San Ramon.

Planting Calendar for Nierembergia

Frost tolerance for nierembergia:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since nierembergia do not do well in cold weather it is important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant nierembergia in San Ramon is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant nierembergia and expect a good harvest is probably September. Any later than that and your nierembergia may not have a chance to grow to maturity. If you are starting your nierembergia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in San Ramon. 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 not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in San Ramon there is a last frost after February 15 so just be sure to be ready to cover your nierembergia 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.