One of the first steps you take when you are determining 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.

You can figure out when it's a good idea to plant common hollyhock in San Luis Obispo by referring to the USDA zone info.

Planting Calendar for Common hollyhock

Frost tolerance for common hollyhock:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Common hollyhock are one of those plants that can tolerate a little bit of cold weather which tells us that you can plant them a little bit earlier than more sensitive plants.

The earliest that you can plant common hollyhock in San Luis Obispo is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant common hollyhock and expect a good harvest is probably October. You probably don't want to wait any later than that or else your common hollyhock may not have a chance to really do well. If you are starting your common hollyhock indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on February 15 in San Luis Obispo. You can expect an average low temperature of 25°F in the coldest months of winter.

Keep in mind that USDA zone info for San Luis Obispo is an average and the actual date of last frost will vary from year to year. Since half of the time in San Luis Obispo you get a frost after February 15 be ready to cover your common hollyhock in the event of a late frost.

USDA Zone Info for San Luis Obispo

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 Luis Obispo

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