Cool Radishes

This was published in the June 3, 2021 edition of The Fish Wrap.

Our radishes are great this year - plump and red and not too hot! Unlike carrots and beets, radishes do not get sweeter the longer they are in the ground - they just get angrier! Radishes like a cool, wet Spring like this year. It can be tricky to find the sweet spot of temperature and hours of daylight with early season crops. A tool that farmers use to find these sweet spots is Growing Degree Units (GDUs).

GDUs are a measurement of temperatures used to predict plant maturity. To calculate the amount of GDUs produced on a given day, subtract the critical temperature (the temp below which the species in question will not grow) from the day’s mean temperature (its maximum temp plus minimum temp, divided by two). Different veggies and even different varieties will have different GDUs. And you need to consider the GDUs of your area since plant development will be delayed four days in the spring for every degree of latitude north you head.

A few degrees of base temperature can make all the difference. For example, the base temperature of wheat and lettuce is 40, sunflower and potato need 45 and summer crops like sweet corn and tomato like 50. Kale has a low and high range of 40-74, while it’s optimal range is 60-65. If you have two crops with different GDUs, you can either plant them at different times or harvest them at different times. It takes planning to harvest when veggies are at their best!

If you do end up with angry radishes, you can do what my Mom did - cut slits in a checkerboard pattern, or if you want to get fancy, carve a radish rose. Then soak the radishes in ice water for 45 minutes until they become mild enough to eat.