Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Phoenix should be reffered to in order to figure out when it's the best time to plant lobelia.

Planting Calendar for Lobelia

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

Since lobelia are very cold tolerant you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant lobelia in Phoenix 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 lobelia and expect a good harvest is probably October. If you wait any later than that and your lobelia may not have a chance to fully mature. You can get started a few weeks earlier by starting your lobelia indoors.

Last Frost Date

On average the last frost has passed is on February 15 in Phoenix. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Phoenix is not always accurate the actual date of last frost changes from year to year. Half of the time in Phoenix there is a last frost after February 15 so be sure to be ready to cover your lobelia in the event of one of those late frosts.

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.