How to Grow: Radishes
Updated: Jul 30
Earliest Root Crop of the Season: The Radish
Radishes are a quick growing cool-season root vegetable. They have been around for thousands of years grown in China, the Mediterranean and in Egypt before the pyramids were built. They are a member of the Cabbage family and are one of the earliest of crops to be harvested in the spring. They are the unofficial start to the garden season.
Spring versus Winter Radishes
There are two types of radishes, spring and winter or daikon radishes. They have some similarities but also have distinct differences.
- Small in size, salad types usually takes around 28-35 days to grow.
- Can be red, pink, purple, yellow, white, and green.
- Planted in early spring and quick turn around, can be a great intercrop.
- Best harvested when small and everything is edible.
- Does not store for long.
- Medium in size, usually takes around 60-75 days to grow.
- Marvelous for soups, stews and stir fries.
- Planted in late summer and early fall, bolts really easily in the summer heat.
Always Direct Sow
It is advised to direct sow radish seedlings outdoors. Radishes become more pungent in hot weather, which is why it's best to grow in cooler weather. To ensure good quality radishes - growth must be continuous and rapid. They have specific needs:
Germination will happen within 3 to 4 days,
Best quality and root shape grow around 10 to 18°C with good moisture.
Germination will decline sharply when soil temperature falls below 13°C continuously.
Planting & Soil Preparation
Radishes are a cool season root crop but they still need a sunny spot. Radishes need a well draining soil, no rocky or gravel in the mix. Soil should be well-draining and the amount of manure and compost doesn't have to be high. Root crops do not particularly do well in high nitrogen soil as it will encourage more foliage than root vegetable.
Seed depth should be 0.5 to 1 cm.
Space rows 20 to 30 cm.
Smaller radishes like spring radishes should be spaced 2" apart
Bigger radishes like daikons or winter radishes should be spaced 4" apart.
Root crops don't have a particularly high requirement for nitrogen. Ideal for following an area that previously having:
Brassicas: cauliflower, cabbages, Brussel sprouts, kale and radishes*.
The Onion family: onions, garlic, leeks and shallots.
Salads and Leafy vegetables: lettuce, spinach and Swiss chard.
*Radishes are a root vegetable from the Brassica family.
Like most seeds, keep them evenly moist and never let the top of the soil dry out before they have sprouted.
Unlike most vegetables, root crops have very shallow roots. They do love a deep soak every 3 days (unless there was a down poor in-between). No need to water them daily once they have sprouted. Make sure that radishes get an 1 1/2 inch of water a week.
Radishes are a fickle crop, make sure to harvest them on time as they do not hold well in the ground. If left there too long they can get woody.
You'll notice they are ready by the size of the root bulb, not necessarily by the foliage. Radishes can grow big beautiful foliage and never develop a root to eat.
When ready - simply tug them by their greens, ever so gently, and brush away any dirt from the roots. It's that simple.
Radishes do not store for long. A quick trick to keeping radishes for a longer period is by:
Top them and store them unwashed at a near freezing temperature in a plastic zip-top baggie.