Radishes are among my favourite garden crops, and I am getting ready to make my third spring sowing. All of my plantings have a reasonable chance of success, because I am committed to spoiling the little darlings with indulgent care - the first truth I must tell about growing radishes. Just because radishes grow fast does not mean they are easy or carefree. Here are seven more truths about growing radishes.
Radishes don’t grow as quickly as they say
Radishes can mature really fast, but not always. American seed companies often promote the earliest radishes as maturing in 23 days, which I have never seen happen in my garden. British catalogues give a more reasonable estimate of four to six weeks, which factors in periods of slow growth due to cool, cloudy weather. I always allow at least six weeks for a good crop of spring radishes, and ten weeks for radishes grown in the autumn.
Radishes need space
The fast growth of radishes comes with conditions, including an uncompromising need for space. Seedlings that grow too close together will not plump up, so you must either sow the seeds at uniform spacing or thin them soon after they sprout. Small salad radishes will mature nicely when thinned to 2 inches (5cm) apart, but allow 4 inches (10cm) between big daikons and other storage radishes. Note that radish seed tapes can be a huge help with spacing, and they are fast and easy to make.
An easy life makes for a successful crop
Radishes have no tolerance for weeds or moisture stress, and they must have soil that never dries out. Early-season mulches invite problems with slugs in my rainy climate, so attentive watering is the only solution when growing radishes. Lettuce has similar needs, so I often grow the two vegetables in adjacent rows.
Only certain types of radish grow well in spring
All radish varieties grow well in the fall, but only some excel in the spring. Fast-growing salad radishes in red, bicolours, or pastel Easter egg colours are top choices in spring, but the only Asian radishes I have found that grow well from spring sowings are Chinese types such as ‘Dragon’ (the long red radishes in the photo at the top of the page). Beautiful red and green “watermelon” radishes like ‘Misato Rose’ and carrot-shaped daikons are always better in the autumn.
Pest and disease problems are always just around the corner
Radishes are not without their problems. Flea beetles make tiny holes in the leaves, slugs and snails chew grooves in perfect roots, and a sudden deluge can cause radishes to split and start rotting. These are but a few of the reasons to promptly harvest radishes that have popped up out of the ground, trim off their tops, and store them in the refrigerator.
Prompt harvesting is essential
Despite claims that some radish varieties will hold in the garden without becoming pithy, the truth is that many bad things can happen to radishes that are left unharvested a day or two too long. It is a paradox that while perfect radishes must be promptly harvested, the trimmed roots will store in the refrigerator for months.
Radishes are very versatile in the kitchen
Radishes are delicious eaten raw, but they are also a savoury cooked vegetable that deserves wider use in roasting pans and soup pots. Radishes are a great little vegetable for fermenting, too. When you use salt fermentation methods to pickle little salad radishes, cut in half, the colours meld to produce a bright pink pickle.
The bottom line is that while growing radishes can be more intensive compared to many other vegetables, attending to details will ensure a successful crop.