The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can estimate when it's possible to plant black radish in San Juan by looking at 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.

You can plant black radish just a bit earlier in the year because they do well in moderate cold.

The earliest that you can plant black radish in San Juan 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 black radish and expect a good harvest is probably October. 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. If you are starting your black radish indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In San Juan the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Keep in mind that USDA zone info for San Juan is not always accurate and the actual date of last frost is different every year. Since half of the time in San Juan you get a frost after February 15 be ready to protect your black radish if you have a late frost.

USDA Zone Info for San Juan

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 San Juan

You may be interested in your other planting guides for San Juan.