One of the best tools that you have as gardeners to help us figure out 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.

A common way of figuring out when it's a good idea to plant oxalis is to look at the USDA zone info for Petaluma.

Planting Calendar for Oxalis

Frost tolerance for oxalis:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Oxalis are not cold tolerant which means that you have to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant oxalis in Petaluma is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant oxalis and expect a good harvest is probably September. You probably don't want to wait any later than that or else your oxalis may not have a chance to really do well. You can get started a couple of weeks earlier by starting your oxalis indoors.

Last Frost Date

The average date of last frost is February 15 in Petaluma. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Petaluma is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Petaluma there is a last frost after February 15 so make sure that you are ready to cover your oxalis in the event of a 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.