Radish seeds: Drop ’em in the ground with abandon; within three weeks, voila! Radishes, ready for eating. Fast is why they’re a favorite vegetable of beginning gardeners: Throw a seed in, stand back awhile, and soon some greens emerge.
But fast also means hidden secrets. If you treat them like all other quick fixes your radishes may end up woody-tasting and awful one year. Typically it boils down to two thing, soil temperature, and timing. The chart above explains these. Knowing what window is makes a big difference.
How to Grow Radishes
Cool soil. Between fifty-five and seventy-five degrees Fahrenheit on average, any warmer and the germination rate decline. Before plants get their good footing they might bolt to go to seed. It is best sown in spring and fall, when weather’s cooler. In summer, radishes will cook themselves, turning hot and watery and fibrous and all stem instead of being round and nice.
Consistent moisture are essential, so that the roots plump up evenly. Letting the soil dry out causes them to become fibrous (and even crack). Keep it moist and they’ll be crisp-fleshed. Sound easy? Most gardeners mess up on this one: watering. Once those fast crops is in the ground, you’re likely to forget about them. From sprout to harvest, radishes require some attention.
Then there’s everyone’s least favorite task: thinning. Crowded radish will be pale and skinny because they aren’t getting enough space or nutrients. Provide one inch between plant so that each has some elbowroom to grow. The how-to photo series recommends waiting till after true leaves emerge before thinning, which sounds about perfect. If you wait longer and try to remove the extra when the root has formed complete, you’ll have trouble extracting them without uprooting desired plants. You will sacrifice a few seedling to get something much better later on.
Not all radishes are created equal. Many home gardeners gets tripped up by this: There’s a difference between winter storage radishes and spring globes (see chart). For instance, something called a Cherry Belle is a spring radish, quickly maturing in roughly three weeks. It is perfect for relay planting, which means sowing another row every ten days for a continuous crop.
On the other end of spectrum, a winter type like Black Spanish or even Daikon takes almost two months to mature, requires wider spacing and deeper soil, since these radishes will gets much bigger. Haste makes waste, you’ll never enjoy a tasty root if you try to push a winter radish to fit a spring time line. Match variety to your patience level (and your calendar).
Eventually, all those leaves divert their energy toward the root as it matures. At first, most of the biomass go into making more leaves (cotyledons followed by true leaves). Then, most of the energy goes into fattening up edible part. That’s when time starts running out. For best flavor, harvest at just-right size; a one-inch root is tastier than a two-inch root that’s gotten bitter and pithy. Don’t let pride of yield override taste. You should of don’t do it.
Radishes are gentle, yes, but not magical: Give them what they want, and they’ll give it back. With awareness of their growing stages (the visual below), spacing, and soil temperature, you’ll go from hoping for a radish to engineering one. When your next seed goes into the ground, keep in mind that the actual work is underground. Moisten the soil, thin promptly, and pick them young. Maybe the easiest vegetable in garden will also yield the quickest return.