One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant celosia in San Francisco can be figured out by reviewing the USDA zone info.

Planting Calendar for Celosia

Frost tolerance for celosia:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since celosia require warm weather you need to wait until after the last frost has passed before you can plant them.

The earliest that you can plant celosia in 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 celosia and expect a good harvest is probably September. If you wait any later than that and your celosia may not have a chance to fully mature. Starting your celosia indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in San Francisco. You can expect an average low temperature of 35°F in the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for San Francisco and it will vary from year to year. Since half of the time in San Francisco it frosts late in the year after January 31 be ready to cover your celosia in the event of one of those late frosts.

USDA Zone Info for San Francisco

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in San Francisco

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