What do you picture when someone says “radish”? I’ll bet it’s bright, shiny little red spheres with white flesh, right? Well, that’s not always the case: ever heard of watermelon radishes? They don’t look like radishes you find in your grocery’s produce department, and don’t taste like them, either.
The familiar red-and-white color scheme is backwards in watermelon radishes: this kind has a thick, somewhat tough whitish skin wrapped around crisp, deep red to purple flesh. In taste, they are "tangy" when they’re small; almost tasting like good quality horseradish. When fully-grown, the taste is somewhat mellower. Burpee’s radish variety grows to a full size of 3-4” diameter, though hot weather stunts them somewhat.
My Burpee Watermelon Radish Seeds had excellent germination -- at least 95% -- which is especially good considering that I planted them two years after the year on the label. Like all radishes, you plant these seeds in about ½” of fine soil. They germinate and poke up their first leaves in 5-7 days, at which time you should thin the seedlings to 2” spacing: if they're left un-thinned, the bulbs won’t develop properly if at all. They're sensitive to the heat and will perform a little better as a fall crop in hot climates. If there’s no hard frost, they will even overwinter. Both their color and taste are fine additions to salads, though newbies might think they're beets at first glance. They also work well in those rare dishes calling for cooking radishes.
You'll need extra patience to grow watermelon radishes: they take somewhat longer to mature than those classic red and white Cherry Belles; about 55 days compared to 25. When you harvest them, though, you're in for a taste treat - not to mention that you'll surprise people with your "backwards radishes."