Before planting it is a good idea to find your USDA Zone info to figure out 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 Portland can be reviewed to figure out when it's a good idea to plant radishes.

Planting Calendar for Radishes

Frost tolerance for radishes:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Radishes do well in cold which means that you can plant them much earlier than plants that are more sensitive to the cold.

The earliest that you can plant radishes in Portland 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 radishes and expect a good harvest is probably October. You probably don't want to wait any later than that or else your radishes may not have a chance to fully mature. You can get started a few weeks earlier by starting your radishes indoors.

Last Frost Date

The average date of last frost is February 15 in Portland. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Portland may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Portland last frost occurs after February 15 be ready to cover your radishes if you have one of those late frosts.

USDA Zone Info for Portland

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 Portland

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