Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Phoenix can be looked at to determine when it's the best time to plant bidens.

Planting Calendar for Bidens

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

It's a bad idea to plant bidens until after the last frost because they are not cold tolerant.

The earliest that you can plant bidens in Phoenix 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. You probably don't want to wait any later than that or else your bidens may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your bidens indoors.

Last Frost Date

On average the last frost is on February 15 in Phoenix. It might get as low as 25°F during the coldest months of winter.

Remember that USDA zone info for Phoenix is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Phoenix you get a frost after February 15 be ready to protect your bidens if you have a surprise late frost.

USDA Zone Info for Phoenix

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 Phoenix

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