Lesson 1: Preparing to Sow
1.1) Basic Preparation
Just because radishes are an obliging lot doesn’t mean that you should ignore the basics. Pick a sunny – but not too sunny – spot. Radishes like the sun but they run to seed if they get too much of it. For best results, the radish plot should be dug over at least a month before sowing. But you won’t be the first novice gardener to dig immediately prior to planting radishes. Just make sure you get rid of any stones. Don’t add manure to the soil but do water it. You want a moist seedbed.
1.2) Sowing Strategy
Use a rake to break up the soil, creating a fine “tilth” (surface soil that’s ready to plant). Mark out a row with garden twine and stakes, creating a channel (the correct gardening word is a “drill”) around 1cm-1.5cm deep. Sow your radish seeds thinly in this drill, cover with soil and firm. If you’re planting more than one row, position them 15cm apart. Don’t forget to label your rows. Congratulations! You’ve just sown your first crop. You can now stroll around the local garden centre with your head held high. And, if Alan Titchmarsh comes on the telly, you’re at liberty to nod sagely as he disseminates vegetable lore.
1.3) Try These
“Scarlet Globe” is a traditional, spherical variety that is especially quick to mature – a handy characteristic if you’re growing radishes with children. “Cherry Belle” can stay in the ground without spoiling for a little longer than other varieties. A popular, reliable radish, “French Breakfast” has a cylindrical shape and a cracking flavour.
Lesson 2: Thinning Radish Seedlings
2.1) Rapid Progress
Radishes are quick to please. Under normal conditions, the first seedlings appear in less than a week. After around 10 days, you should have a row of fair-sized seedlings. Nothing beats the excitement of following these first days of a crop’s progress. And, if this is your first stab at growing your own veg, that excitement is very special indeed. Enjoy the moment!
2.2) Making Room
Mind you, this is no time to sit on your laurels. There’s work to be done if you want to raise a crop of perfect radishes. All young plants need room to breathe in order to develop properly. Once they’re big enough to handle (usually 10-14 days), examine the row of seedlings and identify strong-looking plants around 2.5 cm apart. Remove the weaker ones, taking care not to disturb your target seedlings. Don’t forget to water the young plants. If you’re experiencing wet weather, there’s no need to get your watering can out. But, during dry spells, you’ll need to water them at least once a week. Attach a fine sprinkler head to your watering can, to avoid washing away the seedlings before you get a chance to eat them.
2.3) Eliminating Competitors
If radishes don’t like being crowded out by their own kind, they certainly don’t take kindly to competing with weeds for precious resources. Keeping weeds down is about more than just making your vegetable plot look tidy. Every weed in the ground is hogging nutrition that could be going towards making your veggies big and strong. So, show no mercy! Use a hoe to chop up young weeds before they can take hold. If you’re confronted with a deep-rooted weed, use a trowel or hand fork to dig deep and remove the whole plant, including the root. Don’t put deep-rooted weeds into your own compost: they’ll cause problems if you do.
Lesson 3: Harvesting Your First Radishes
3.1) It’s That Time Already
Radishes don’t hang around. If you’re a first-time vegetable grower, the moment you’ve been waiting for could be here! Many radish varieties are ready to harvest after a month so, if you sowed your seeds in late April, it’s time to pull a few for sampling. Radishes are best eaten when young. If they’re left in the ground too long, they start to develop a woody texture and eventually become hollow. In addition, the flavour deteriorates from a lively tang to an unappealing bitterness. Round radishes are ready when they’re about 2cm in diameter. Cylindrical varieties such as “French Breakfast” should be picked when they’re a similar thickness but no longer than your thumb.
3.2) Beating the Birds
One reason why radishes are so popular with novice gardeners is that their rapid progress to maturity means you have another chance to get things right if there have been difficulties with an initial crop. Juicy young radish seedlings can be vulnerable to birds, who always have an eye open for what’s on offer in the vegetable garden. If birds were a problem for your first crop, sow a second batch of seeds and use netting to keep those hungry beaks at bay. Garden centres sell all sorts of netting, which you can drape over some short canes. There are more tips on tackling pests in the next lesson.
3.3) Second Go
Re-sowing a second batch of radishes is a good idea, however successful the initial crop was. After all, if your first lot of radishes was a hit, you’ll want to repeat it! Sow a second crop of seeds in the same way as the first. Continue to sow more seeds at fortnightly intervals until August to ensure an uninterrupted supply of radishes all summer.
Lesson 4: Harvesting and Protecting Radishes
4.1) Next Generation
You may well have finished harvesting your first crop of radishes by now. If you haven’t, give them away to family and friends rather than leave them in the ground. Radishes should be eaten young and they don’t keep for long, either. Meanwhile, if you planted a second crop a fortnight ago, the seedlings should be ready for thinning to 2.5cm gaps. Look after them as you did for the first crop but check out the advice below for strategies to combat pests and diseases. It’s also time to sow a third crop. Re-sowing at fortnightly intervals is the best way to ensure a constant supply of radishes all summer.
4.2) Trails and Tribulations
There is nothing more dispiriting for the novice gardener than finding slug trails all over your young crop. But you can fight back! If you don’t want to resort to chemical deterrents, try surrounding the plants with grit or sharp sand. Cover seedlings with bottomless plastic water bottles. Cut serrated plastic rings from larger bottles to defend bigger plants. A homemade slug trap can work wonders. Slice a plastic water bottle in two just below the neck. Turn the neck bit round and insert it into the body. Tape or staple the two parts together. Fill the trap with sugary liquid and place it near your veggies. If you’re growing radishes in a pot, try sticking copper tape (available from garden centres) just below the rim. Copper naturally carries a slight electrical charge that discourages slugs.
4.3) Preventing Pests
Unfortunately, slugs aren’t the only pests you’ll face, although radishes don’t have as many enemies as some vegetables. Flea beetles attack the leaves of seedlings, leaving small, round holes. They are attracted to dry plants, so keeping your crop well-watered is a good deterrent. Cabbage root flies attack the roots, causing stunted growth and a bluish discolouring of the leaves. The best prevention is to surround the plant with a disc of strong black plastic or a stout material like roofing felt. This stops the flies laying eggs in the soil around the roots.
Lesson 5: Extending Your Radish Harvest
5.1) Catch Me If You Can
One of the advantages of a quick-growing vegetable like the radish is that it can occupy space left by other crops but still have enough time to mature by the end of summer. This type of vegetable-growing is known as “catch-cropping”. You can use this technique if you’re also following our lettuce-growing course, for example. Once your cos lettuces have finished, sow radishes in the space left behind. (This doesn’t work for cut and come again loose-leaf varieties, of course: they’ll be in the ground all summer.) Be aware that radishes can suffer if they’re exposed to too much midsummer sun. But lettuces are best grown in an area with some shade, anyway, so this catch-crop twinning is a good combination.
5.2) Late Summer Bounty
Even if you’re not employing a catch-cropping technique, now is a good time to sow a few more radishes for harvesting towards the end of the summer. As with catch-cropping, just make sure you don’t choose too sunny a spot. Very warm and dry conditions can result in over-hot radishes that fail to form a proper bulb.
5.3) Solving Problems
Radishes are one of the easiest veggies to grow successfully, so you’re unlikely to have had too many problems so far. But difficulties do arise. Sometimes, bulbs fail to mature properly. This can be because of hot, dry conditions (see above). Another cause is that they haven’t been thinned properly. If they’re too close together, the radishes will be competing for scarce resources. Check the correct thinning distances given in Lesson 2. If the bulbs are cracked, they have been in the ground too long before being harvested. An uneven watering regime can also cause this condition. Don’t let the ground around your crop dry out and then water them enthusiastically. You’ll be setting yourself up for a bunch of cracked radishes.
Lesson 6: Growing Winter Radishes
You may still have some summer radishes in the ground, ready for harvesting in a few weeks’ time. But there’s no reason why your radish-growing experience has to stop at the end of the summer. Why not have a go at raising winter radishes? These robust members of the radish family come in many varieties. Most of them pack a punch in the flavour department and their hardiness means that you can go on enjoying home-grown produce well into the winter months.
6.1) Deep and Even
Sowing winter radishes is broadly the same as sowing summer varieties but you need to bear one significant factor in mind. Winter radishes are much larger than their dinky summer cousins. So the seedbed must contain fine, even soil to a depth of at least 30cm. The plants also need to be further apart if they are to develop properly. In late July or early August, sow groups of 3 or 4 seeds at 15cm intervals in 2cm-deep drills. Space the drills 30cm apart. After 7-10 days, or when the seedlings are big enough to handle, remove the weaker seedlings, leaving one strong young plant every 15cm.
Look after young winter radishes in the same way as summer varieties. Water and weed the seedlings carefully. Keep slugs at bay. The bushy foliage will help keep weeds down once the plants are bigger. Winter radishes are usually ready to eat 10-12 weeks after sowing. They can stay in the ground longer, provided that you cover their crowns with straw or similar material. Many gardeners prefer to lift their winter radishes in October or November and store them. Twist off the foliage, rub off the dirt and put them in a box of sand. Place the box in a cool, frost-free location and the radishes will keep for months.
6.3) Try These
“China Rose” is a popular winter radish. The oval roots grow up to 15cm long. “Mino Early” radishes are 30cm long, slim and white. The mild flavour makes them useful for winter salads. Red-fleshed “Mantanghong” is an attractive variety that can be used for both cooking and salads.