Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Portsmouth should be reviewed to estimate when it's possible to plant black radish.

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 tend to make it in mild cold which means that you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant black radish in Portsmouth 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 really do well. Starting your black radish indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Portsmouth. It might get as low as 10°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Portsmouth is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Portsmouth last frost occurs after March 15 so always be ready to cover your black radish in the event of a surprise late frost.

USDA Zone Info for Portsmouth

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 Portsmouth

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