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 determining when it's a good idea to plant romanesco is to check out 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.

Since romanesco are one of those plants that can tolerate a little bit of cold weather you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant romanesco in Phoenix is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant romanesco and expect a good harvest is probably September. If you wait any later than that and your romanesco may not have a chance to fully mature. Starting your romanesco indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on March 15 in Phoenix. You should expect an average low temperature of 10°F in the coldest months of winter.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Phoenix and it will vary from year to year. Half of the time in Phoenix there is a last frost after March 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 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.