Why Your Radishes are Spicy and How to Cook with Them

Why are my radishes spicy? There are a few reasons why radishes become overly pungent and spicy. Hot weather, insufficient water, and letting it grow past the peak stage are the main culprits. Unlike carrots, the longer they are in the ground, the spicer they will become.

One year I planted watermelon radishes across a span of three succession plantings. I sowed the seeds during the same time frame that you would normally do for a breakfast radish. I didn't take into account that it takes three times as long to mature than your average red radish. The weather got pretty warm by the time I pulled them. The small ones were perfect, but the large ones were far too spicy to eat raw.

Another reason causing spiciness is insect pest damage. According to Jordan Tony, our resident garden specialist “the compounds that make them spicy, Allyl isothiocyanates, are defense chemicals that the plant uses to ward off herbivores which is why most of the spiciness is on the outside of the radish. It's the same compound that makes mustard and horseradish spicy.”

That season, I learned that homegrown vegetables, like wild game, don’t always taste like the stuff you get at the grocery store. They vary greatly in flavor and texture based on their growing conditions, and instead of throwing out those extra-spicy radishes, I found creative ways to make the best of them.

Peel The compound responsible for the spiciness is on the outer skin of the radish and you can remove it with a vegetable peeler. You can also soak them in ice water for an hour to tone down the heat.

Pickle I love pickled radishes. The vinegar tames the pungency and turns them into a bright and acidic condiment for dressing sautéed greens, salsas, and rich meats. I especially love soaking diced radishes in lime juice to use as a substitute for jalapeno in pico de gallo.

Cook You can tone down the heat by applying heat! I love pan-frying radishes with a good dollop of clarified butter or duck fat, then adding some fresh woody herbs, such as rosemary or thyme and a good pinch of kosher salt and freshly cracked black pepper. They can also be roasted or grilled and make a fantastic substitute for potatoes. They're earthy, peppery, and offer a nice change to the traditional starchy side dish.

Grate If your radishes are as spicy as a horseradish root, why not use them as a substitute? I like to grate radishes on a microplane and add the vibrant pink pulp to mayo or sour cream to use as a sandwich spread, on top of potatoes, or to ponzu sauce for sushi or Asian fish recipes.

The next time you grow a handful of overly spicy radishes, try one of these tricks instead of dumping them into the compost or trash bin. You'll have a newfound respect for these beautiful pink roots.