The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of determining when it's possible to plant nierembergia is to consult the USDA zone info for South San Francisco.

Planting Calendar for Nierembergia

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

It's a bad idea to plant nierembergia until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant nierembergia in South San Francisco 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 nierembergia and expect a good harvest is probably September. If you wait 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

In South San Francisco the average date of last frost happens on January 31. It might get as low as 30°F during the coldest months of winter.

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 South San Francisco and it changes from year to year. Half of the time in South San Francisco there is a last frost after January 31 so make sure that you are ready to protect your nierembergia if you have a late frost.

USDA Zone Info for South San Francisco

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 South San Francisco

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