Before planting it is a good idea to find your USDA Zone info to figure out 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.

A common way of estimating when it's the best time to plant romanesco is to look at the USDA zone info for Phoenix.

Planting Calendar for Romanesco

Frost tolerance for romanesco:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant romanesco a little bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant romanesco 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 romanesco and expect a good harvest is probably October. Any later than that and your romanesco may not have a chance to really do well. You can get started a few weeks earlier by starting your romanesco indoors.

Last Frost Date

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

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Phoenix and it 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 romanesco 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.