Considered one of the easiest vegetables to grow, radishes are a hardy root vegetable that can be planted multiple times in a growing season, and can also be harvested as soon as 3 weeks after planting. While radish seeds can be planted in both the spring and the fall, the growing process should be suspended in mid-summer when temperatures are generally too hot. Hot temperatures may result in radishes bolting, making them essentially pointless.
Planting and Growing Information:
Be sure to plant radishes in a sunny spot. If radishes are planted where there’s too much shade, or even where neighboring vegetable plants shade them, they will put all their energy into producing larger leaves. Before planting, till your garden bed to remove any rocks or dirt clods. Radish plants are predominately grown for their roots, just like carrots. Establish the habit of a 3-year crop rotation, meaning that you only plant radishes in the same spot every third year, which will help prevent diseases from affecting your crop. If you want to plant in the spring, sow seeds 4 to 6 weeks before the average date of your last spring frost. If you wish to plant in the fall, this is also possible. You can plant radishes later than any other root crop in the late summer or early fall and still get a harvest. Be sure to sow seeds 4 to 6 weeks before the first fall frost.
Since radish seeds have a fairly long shelf life, you can easily plant radish seeds that are up to 5 years old. While all of them may not germinate, you will have plenty that will. To avoid disturbing their roots, it’s best to sow radish seeds directly in the garden. Directly sow seeds outdoors ½ to 1 inch deep apart in rows 12 inches apart. For a continuous harvest of radishes in the late spring and early summer, sow another round of seeds every 10 days or so while the weather is still cool.
Since crowded plants don’t grow well, be sure to thin radishes to about 2 inches apart when the plants are a week old by snipping the greens at the soil line. If thinnings have been carefully pulled with roots, leaves, and stems intact, replant them. While transplants might be slightly stressed, they should recover. It is important to weed regularly to reduce competition to radishes. Consistent, even moisture is key; make sure to keep soil evenly moist but not waterlogged. To help retain moisture in dry conditions, put a thin layer of mulch around the radishes.
The soil needs to be rich in organic matter, but it shouldn’t be compacted. If your soil is more clay-like, mix in some compost to loosen it and improve drainage. As soon as the soil is workable, incorporate a few inches of aged compost of apply all-purpose fertilizer into the planting site. Radishes don’t require additional fertilization after they’re planted.
Radishes will be ready to harvest relatively quickly, as soon as 3 weeks after planting for some varieties. Harvest when roots are approximately 1 inch in diameter at the soil surface for most varieties. Before harvesting the rest, pull a radish out and test it. Make sure to not leave radishes in the ground long after their mature stage as their condition will deteriorate rapidly. If the weather is cool, keep winter radishes in the ground for a few weeks after they mature. Be sure to finish the harvest before frost.