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.

The first chance to plant violas in Sonora can be estimated by using the USDA zone info.

Planting Calendar for Violas

Frost tolerance for violas:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Violas tend to make it in quite a bit of cold which means that you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant violas in Sonora 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 violas and expect a good harvest is probably October. You probably don't want to wait any later than that or else your violas may not have a chance to fully mature. If you are starting your violas indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Sonora the average date of last frost happens on February 15. It might get as low as 20°F during the coldest months of winter.

It's important to remember that USDA zone info for Sonora is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Sonora there is a last frost after February 15 so be sure to be ready to protect your violas 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.