One of the first steps you take when you are getting a good idea 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.

By referring to the USDA zone info for Sonora it's possible to estimate when it's a good idea to plant bidens.

Planting Calendar for Bidens

Frost tolerance for bidens:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Bidens are not cold tolerant which means that you have to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant bidens 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 bidens and expect a good harvest is probably September. If you wait any later than that and your bidens may not have a chance to grow to maturity. You can get started a little bit earlier by starting your bidens indoors.

Last Frost Date

The average date of last frost is February 15 in Sonora. You can expect an average low temperature of 20°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Sonora is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Sonora you get surprised by a frost after February 15 be ready to cover your bidens if you have a late frost.

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.