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.

The first opportunity to plant black radish in Denver should be estimated by referring to the USDA zone info.

Planting Calendar for Black radish

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

Black radish can survive in a little bit of cold which means that you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant black radish in Denver 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. You probably don't want to wait any later than that or else your black radish may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your black radish indoors.

Last Frost Date

In Denver the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in the coldest months of winter.

Remember that USDA zone info for Denver is just an average and the actual date of last frost is different every year. Since half of the time in Denver it frosts late in the year after April 15 be ready to cover your black radish in the event of a surprise late frost.

USDA Zone Info for Denver

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Denver

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