The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of estimating when it's the best time to plant borage is to look at the USDA zone info for Petaluma.

Planting Calendar for Borage

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

Borage do well in mild cold which tells us that you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant borage in Petaluma 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 borage and expect a good harvest is probably October. Any later than that and your borage may not have a chance to really do well. Starting your borage indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Petaluma the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Petaluma may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Petaluma you get a frost after February 15 be ready to cover your borage in the event of a surprise late frost.

USDA Zone Info for Petaluma

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 Petaluma

You may be interested in your other planting guides for Petaluma.