Radishes are a fast-growing root crop that can be added to almost any garden, no matter how big or small. Radishes add a nice kick to salads and soups, so radishes are generally eaten in small quantities; and they can be a good source of vitamin C and fiber.
The best part about growing radishes is how quickly they mature. In most cases, a radish will be ready to harvest in under a month. Due to their growth rate, you can plant radishes in between slower growing crops, for a dual harvest, in the same amount of space.
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Radish Varieties
Radishes come in three main varieties: Spring, Summer, and Winter.
Spring Radish
Spring radishes are the ones most commonly found at the grocery store. Spring radishes grow the fastest and tend to prefer the cool weather of the spring and fall.
Summer Radish
Summer radishes tend to grow slower, taking up to eight weeks to mature.
Winter Radish
Winter radishes are much larger, with long starchy roots, that grow best when sown in the late summer, for a late fall harvest. Winter radishes, such as Daikon, can be used to improve poor soil with their roots that can reach 1.5 ft (2.2 m) deep.
When Should You Plant Radishes?
Radishes prefer to grow in cool weather, making spring and fall the best times to grow them. Starting radishes indoors for transplant is usually not recommended, as radishes do very well when they are directly sown into the garden.
For a spring crop, after as all danger of frost has passed, you can plant the seeds as soon as possible. When planting the seeds in the fall, wait until the air temperature has fallen below 60 Fahrenheit (16 C). If you grow radishes at temperatures above this mark, you risk the plant going to seed, as this will cause the root to become woody and inedible. In all but the shortest growing seasons, almost anyone can get a good yield of fully mature radishes.
Planting Radishes
Radish Soil Requirements
Radishes need a soil free of obstructions, in order to produce quality roots. If you cannot reasonably provide these conditions, you can always set up a raised bed (Buy Online). Radishes need to be planted in a location that has full sun exposure, and they will grow well in most climates. The soil should also have adequate drainage, in order to prevent molds and root rots.
If your soil has a high concentration of clay, or if it tends to collect puddles of water, you can add some compost, along with a generous amount of sand, which will improve drainage and prevent your radishes from rotting in the soil.
Radish Soil pH
Your soil pH should be between 6.0 and 7.0. Once your soil is ready, you can start sowing the radish seeds.
Radish Plant Spacing
Radish seeds should be planted 0.75 inches (1.9 cm) deep, with a spacing between plants of 3 inches (7.6 cm).
Radish Water Requirements
Once the radish seeds have emerged, they will require about 1 inch (2.5 cm) of water a week. You should water multiple times a week. Be careful to avoid over-saturating the soil, in order to limit the risk of the root cracking due to water stress.
While the plants are young, weeds may begin to overcrowd the seedlings. If this happens, remove the weeds carefully, as radishes have a very shallow root system that can be easily damaged. If possible, add a layer of mulch around your plants, in order to prevent weeds from taking over the area and minimize the need for frequent watering.
Radish Care & Harvest
Radish Pests and Diseases
Most of the time, radishes are very easy to care for during their short growing season. Just keep an eye out for any insect damage or fungal infestations, as the plants mature. If you see tiny holes in the leaves, you may have flea beetles. They can be controlled with insecticides (Buy Online) or by carefully cultivating the soil around the base of the plants.
Radish Root Maggot Control
If you notice the leaves fading and turning yellow, with noticeable tunnels in the roots, then you might have root maggots. The best way to combat a root maggot problem is to apply lime around the base of the plant or to avoid growing the radishes in damp conditions.
Don’t Over Water Radishes
Moisture is also the main driver of fungal diseases, such as leaf spot, downy mildew or black rots. If you spot any fungal problems, make sure to quickly remove any infected plants and try to reduce the water the plants get for a short period.
Harvesting Radish Greens
Radish greens, while not commonly consumed, make a nice addition to salads and can be harvested early on in the season. Make sure to choose young tender leaves, no taller than 4 to 5 inches (10 to 12 cm). Use a sharp blade or scissors, and make a clean cut at the base of the stem, while trying to leave the center leaves in place, so the plant can continue its growth.
When are Radishes Ready to Pick
The best time to harvest radish roots is when they are young and tender because older plants might provide a larger root, but the texture might be less appetizing. Radishes are ready for harvest when they are 1 to 3 inches in diameter (2.5 to 7.5 cm).
Carefully pull the plants from the soil, gently knocking off any residual dirt; twist the greens off, at about 1 inch (2.5 cm) above the root; and then clean the root off with cool water. Radishes can be stored in the refrigerator or root cellar for a couple weeks.