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.

A way of estimating when you can plant black radish is to check out the USDA zone info for Flagstaff.

Planting Calendar for Black radish

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

Since black radish are moderately cold tolerant you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant black radish 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 black radish and expect a good harvest is probably September. Any later than that and your black radish may not have a chance to fully mature. You can get started a little bit earlier by starting your black radish indoors.

Last Frost Date

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

Just be sure to remember that USDA zone info for Flagstaff is not always accurate and the actual date of last frost is different every year. Half of the time in Flagstaff it frosts late in the year after April 15 so just be sure to be ready to cover your black radish if you have a 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.