When to Plant Radishes in Ottawa, IL

The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when it's the best time to plant radishes in Ottawa by reviewing the USDA zone info.

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Planting Calendar for Radishes

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

Since radishes do well in cold you can plant them much earlier in the year than other frost tender plants.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant radishes
Possibly ok, but a risky time to plant radishes
Probably not a good time to plant radishes

The earliest that you can plant radishes in Ottawa 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 radishes and expect a good harvest is probably September. You probably don't want to wait any later than that or else your radishes may not have a chance to fully mature. If you are starting your radishes indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Ottawa. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Ottawa may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Ottawa you get a frost after April 15 so make sure that you are ready to protect your radishes if you have a late frost.

USDA Zone Info for Ottawa

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 Ottawa

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