Days to germination: 5 to 10 days
Days to harvest: 21 to 28 days
Light requirements: Full sun, or light shade
Water requirements: Regular watering
Soil: Loose, drained, low nitrogen
Radishes are often the first vegetables people get to grow themselves as a child. They’re easy, have big seeds and can be harvested in less than a month. The perfect vegetable to teach children about gardening.
It also makes them ideal for grown-up gardens too. They grow quickly and you can harvest them even before some plants go into the ground, allowing you to get double usage from parts of your garden plot.
Radishes can range from very mild, to really hot and peppery. Part of their flavor comes from how they are grown but you can choose varieties that are known to be hotter. Most radishes are short and round though some varieties are long like carrots. Radishes come in red, white, pink or purple. White Icicle radishes look like white carrots, and are a very unique vegetable for your table. Purple ones like Black Spanish look almost like tiny little beets.
They make a tasty snack or addition to a salad. Though they can be cooked, radishes are more typically eaten raw. The roots are mostly water, but also have vitamin C and folic acid.
Starting from Seed
Don’t bother trying to start seeds indoors or transplanting your radishes. Just get outside in the early spring and plant the seeds directly into your garden. Grow your radishes in a sunny spot, and start your seeds out around 3 weeks before your last frost date.
Unlike many other garden vegetables, you don’t need to have overly rich soil for growing radishes. Just dig it through several inches (depending on the length of your radish variety) so the plant can develop its root without rocks or hard clay getting in the way. A little extra compost is fine, but don’t add any fertilizer.
Radish seeds are nice and large to handle, so spacing them out is pretty easy. Keep the seeds 2 to 3 inches apart, and an inch deep in the soil.
Unlike most other cool-weather crops, radishes do just fine during the summer months as well. After your initial seeding, you can keep growing fresh radishes if you plant more seeds every other week.
One of the great joys of radishes is that they don’t require all that much attention while they grow. Another reason you can let kids take care of them.
You do need to keep them well watered, especially when the weather is hot. Lack of moisture can make for hot or even bitter radishes at harvest time. It’s not bad if you like hot radishes but you run the risk of ruining your crop if you don’t give them regular watering. At least twice a week they should be thoroughly watered. Dried out radishes can also end up very hollow inside, or “pithy”.
If you are fertilizing your garden, take care not to give too much to your radishes especially if you are using a high-nitrogen formula. Nitrogen will help your radishes grow thick lush leaves, and almost no roots.
Given their small size and short growing time, they are one of the most perfect vegetables for container gardens. Depending on the size of your radish variety, just about any container will do. Short round radishes work best but even the longer ones will grow fine as long as the container is taller.
Keep your containers well-watered and don’t let your plants dry out. Containers do tend to need more water than gardens, and it’s particularly important with radishes.
Though they like the sun, you can even grow radishes successfully indoors. They will do best in a south-facing window.
Pests and Diseases
Your radishes may have trouble with root maggots, that dig underground and eat holes through the growing radish root. You probably won’t know you have maggots until you go and pull a radish full of holes. The leaves will sometimes start to wilt if the damage is severe enough. The maggots hatch from eggs laid by small flies, so a cover of fine mesh over your plants will keep the flies (and their eggs) away from your radishes.
If you already have maggots in the soil, there is little you can do. Try to pull your radishes as soon as they are edible size, and just hope you get them before the worms do. The longer you leave them in the soil, the more likely they are to be damaged. For the next few years, plant a non-root crop in your radish area (like beans or tomatoes).
Your radish roots aren’t the only vulnerable area. Flea beetles will chew holes in the leaves, which can stunt plant growth. It’s a particular problem when the radish plants are young. They may not cause much harm to established plants. Regular insecticides can help get rid of them.
Harvest and Storage
Radishes are one of the fastest growing vegetables you’re going to find. You can be eating fresh radishes just after the last frost date when the rest of your plants are either just starting or not even planted yet. Just pull them out of the ground by the leaves. Unlike carrots, you really should never need a shovel to get them out.
Try to pull your radishes as soon as they are large enough to eat to minimize any potential damage by root maggots.
You’ll get one radish per seed, so you can gauge your overall harvest by the number of seeds you plant. And don’t forget the leaves. Many people don’t realize that radish leaves are edible, much like how you can eat beet greens as well as the roots. Radish leaves have the same peppery taste as the roots and can be added to salads or cooked (like spinach).
After you pull them, wash the roots off and cut away the leaves. You can store them in your fridge for 2 or 3 weeks before they start to get soft.