One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can estimate when you can plant calendula in Tucson by checking out the USDA zone info.

Planting Calendar for Calendula

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

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

The earliest that you can plant calendula in Tucson 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 calendula and expect a good harvest is probably October. You probably don't want to wait any later than that or else your calendula may not have a chance to grow to maturity. If you are starting your calendula indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Tucson is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Tucson you get surprised by a frost after February 15 so be sure to be ready to protect your calendula in the event of a surprise late frost.

USDA Zone Info for Tucson

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 Tucson

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