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

The earliest that you can plant calendula in Flagstaff can be determined by reviewing 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 are moderately cold tolerant which tells us that you can plant them earlier than other frost tender plants.

The earliest that you can plant calendula in Flagstaff 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 calendula and expect a good harvest is probably September. Any later than that and your calendula may not have a chance to really do well. You can get started a little bit earlier by starting your calendula indoors.

Last Frost Date

The average date of last frost is April 15 in Flagstaff. In the coldest months of winter you can expect an average low temperature of -10°F.

Keep in mind that USDA zone info for Flagstaff is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Flagstaff you get surprised by a frost after April 15 be ready to cover your calendula in the event of a surprise late frost.

USDA Zone Info for Flagstaff

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Flagstaff

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