One of the first steps you take when you are figuring out your gardening schedule is find your 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.

It's a good idea to determine when it's the best time to plant astilbe by referring to the USDA zone info for San Diego.

Planting Calendar for Astilbe

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

You can plant astilbe a bit earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant astilbe in San Diego 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 astilbe and expect a good harvest is probably September. If you wait any later than that and your astilbe may not have a chance to fully mature. You can get started a few weeks earlier by starting your astilbe indoors.

Last Frost Date

In San Diego the average date of last frost happens on January 31. It might get as low as 35°F during the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for San Diego and it will vary from year to year. Half of the time in San Diego it frosts late in the year after January 31 so be sure to be ready to protect your astilbe in the event of a late frost.

USDA Zone Info for San Diego

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 Diego

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