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

In Phoenix you can estimate when you can plant petunias by referring to the USDA zone info.

Planting Calendar for Petunias

Frost tolerance for petunias:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Petunias tend to make it in some cold which means that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant petunias 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 petunias and expect a good harvest is probably August. If you wait any later than that and your petunias may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your petunias indoors.

Last Frost Date

The average date of last frost is March 15 in Phoenix. In the coldest months of winter you should expect an average low temperature of 10°F.

Keep in mind that USDA zone info for Phoenix is just an average and the actual date of last frost is different every year. Since half of the time in Phoenix it frosts late in the year after March 15 be ready to cover your petunias in the event of one of those late frosts.

USDA Zone Info for Phoenix

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Phoenix

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