One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when it's the best time to plant bells of ireland is to consult the USDA zone info for San Diego.

Planting Calendar for Bells of Ireland

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

Bells of Ireland are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant bells of ireland 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 bells of ireland and expect a good harvest is probably September. If you wait any later than that and your bells of ireland may not have a chance to fully mature. If you are starting your bells of ireland indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on February 15 in San Diego. In the coldest months of winter you can expect an average low temperature of 20°F.

Keep in mind that USDA zone info for San Diego is just an average and the actual date of last frost changes from year to year. Half of the time in San Diego you get a frost after February 15 so always be ready to cover your bells of ireland if you have a late frost.

USDA Zone Info for San Diego

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in San Diego

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