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 estimating when it's a good idea to plant oxalis is to consult the USDA zone info for Sonora.

Planting Calendar for Oxalis

Frost tolerance for oxalis:	Not tolerant of frost.
When to plant:	After the last frost.

Oxalis do not do well in cold weather which means that you need to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant oxalis in Sonora 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 fully mature. Starting your oxalis indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Sonora the average date of last frost happens on February 15. You should expect an average low temperature of 20°F in the coldest months of winter.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Sonora and it can change quite a bit from year to year. Since half of the time in Sonora you get surprised by a frost after February 15 be ready to protect your oxalis in the event of one of those late frosts.

USDA Zone Info for Sonora

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 Sonora

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