20 Jan 2022
Raphanus raphanistrum subsp. sativus / Raphanus sativus
If you are an absolute novice to growing your own food, this is the plant to start with. Radish is as easy as vegetable growing gets. The little European spring radishes are super quick to grow (21 – 42 days / 3 – 6 weeks!). Most radishes will grow at any time of year here, are not prone to pests or diseases, will grow in almost any soil and the entire plant is edible, both root and leaves.
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Not everyone likes the peppery heat, crispness and background watery sweetness of raw radish. However you don’t have to eat the root raw. Although it is commonly known as a shaved, grated or julienned addition to salads, radishes can be grilled, roasted and casseroled. Cooking time tends to neutralise the flavour and soften the texture. Radish make chips and soup and peppery sprouts. And of course, pickles; both quick wilted and fermented radish pickles are hugely popular for good reason.
Radish leaves are very edible. The flavour varies wildly according to variety, from neutrally mild to peppery and bitter. The seed pods can be eaten while young and green as an alternative ingredient to the root. You probably already know that the roots come in a wonderful choice of colours – red, purple, pink, white, yellow, green and bicoloured on the outside and usually white inside.
This plant is part of the brassica family but will not cross with other brassicas. Like most others in this family, radish prefers the cooler seasons and is fine with a light winter frost. But, radish will tolerate our summer if you keep it well fed and watered. It does prefer to grow in the shade in summer. The heat or pepperyness and sweetness of radish depend on a number of factors. Different varieties have different heat and sweetness levels. How fast the radish is grown affects the flavour with slow growth resulting in hotter and woodier roots. Radishes left too long become bitter and tough. The season affects the crispness and sweetness too, especially of daikon and mu. According to my Korean recipe book, spring and summer picked mu are insipid and soft (and have their uses) while autumn picked mu is sweet and delicious. There are some radish that need winter frosts to sweeten them.
In this part of the world you can sow radish at any time of year. Generally the best range of soil temperature for germination is 8 – 30°C. For seed saving, some radishes are annuals and others are biennials.
‘European’ radish / spring or summer radish
The inverted commas on European are because this radish probably originated in south east asia. However today the little round or cylindrical radishes such as French Breakfast, Cherry Belle, Purple Plum, D’avignon, Saxa are often eaten raw as they are, or in salads and are very commonly cultivated in Europe as you may be able to deduce from their names. European radish varieties tend to taste quite hot.
There is a variety called München Bier which is grown for eating the peppery crunchy immature green seed pods instead of the root.
Another variety called Spanish Black is an example of a European winter radish. It’s large and pungent and known for it’s long keeping times both in the ground and once picked. Being larger, it takes longer to grow. About 55 days / 8 weeks.
The directions for growing all radishes are very similar.
European spring radish should grow super quickly and can be ready to start eating in as little as three weeks. They should be done in six. Slowly grown radish aren’t very tasty. Because they grow so fast they need amazingly rich soil prepared beforehand. Commercially they are grown in manure rich soil. Aged chook manure is recommended to be added to the soil about 3 weeks before planting in addition to the soil being enriched with compost or aged manure 6 weeks before planting. Ideally soil has a pH of 5.5 – 6.5, is loose and it must be free draining to prevent the roots rotting. But radishes are forgiving.
They are usually sown direct into where they will grow, about 1 – 2 cm deep. Sowing can be quite thick. Expect to thin the seedlings out by picking and eating them as they grow. To have a continuous supply of European spring radish, sow another row only about 5cm away after 3 weeks.
There are two other main requirements for growing radish well. The first is that they need a soft soil above the seed. The baby plants cannot bust through a crusted soil. Cover them with seed raising mix if your soil is likely to seal them underground if it dries out. The second is they need regular watering to keep growing, quite possibly a small daily drink. This is good practice for gardening beginners. Slow growth equals woody and firey radish, more than you might expect or enjoy.
There’s some really interesting variety to explore in Asian radishes, both in frost prone and super hot gardens.
Chinese Shawo Fruit Radish is a radish grown as a winter fruit tasting similar to pear. This hails from northern China, with harsh winters and the frosts are needed to sweeten the radish otherwise it’s quite spicy. Plant about 2 months before frosts are due.
Chinese Red Meat Radish / Watermelon radish is another sweetish radish. White on the outside and red inside. Plant as the weather cools down for winter picking. Ready in 50 days / 7 weeks.
Sakurajima Giant Radish is well named. It hails from the island of Sakurajima in Japan and is enormous, often 7kg and up to 50kg. Takes 90 days / 12 weeks to mature. Plant when the weather begins to cool and harvest in winter.
Raphanus sativus var. Caudatus
Another variety grown for eating the peppery crunchy immature green seed pods instead of the root. Rat Tail is one to note for growing in high high summer especially if your regular radish isn’t as happy as you’d like, because it doesn’t mind sweltering heat at all. The Rat Tail radish variety is common in Myanmar. Ready to eat 45 – 50 days / about 7 weeks after sowing.
Mu / 무 / Korean radish
A large, squat, cylindrical radish, bicoloured with green on the top and white below. Leaves are mild and so is the root compared to European radish varieties. This is a staple in Korean cuisine and the most cultivated vegetable in that country. It is the essential ingredient in a cubed radish kimchee named kkakdugi. Mu are about as fat as daikon but only about 20 – 30cm long. An average weight is around 1.5kg. They usually take 60 – 70 days / 8.5 – 10 weeks to grow. Although it is distinct to daikon, growing instructions are the same, and like daikon, the best ones are considered those picked in Autumn.
Daikon / 大根 / Japanese radish
Raphanus sativus var. longipinnatus
The most popular selling vegetable in Japan. This is a slower growing long, usually white, tapering radish with often hairy and very bitter, though edible, leaves. It too is far milder compared to European radish varieties.
A small daikon is 0.5kg. A large one is 2.5kg. They usually reach 5 – 10cm diameter when mature and about 40cm long, or more. It normally takes 50 – 60 days / 7 – 8.5 weeks in summer and 70 – 80 days / 10 – 11 weeks in winter to grow a small daikon of 500g in Australia. Their favourite growing temperatures are between 20 – 25°C and their preferred minimum soil temperature for sowing is 12°C, a bit higher than European radish. Space them at least 15cm apart. They do prefer a rich soil like the European radishes. However they are very hardy and will just grow and at any time of year in whatever you plant them. If you are a daikon aficionado, give the plant what it likes for the highest quality flavour and texture and note that the best ones are considered to be the ones picked in Autumn.
Daikon isn’t just good for eating. There are field or tilling varieties of daikon that can be so large and dive so deep into the soil they have been found to be quite good at bringing up nutrients from the subsoil and making them available higher up for other plants after they die. They are a strong and determined root vegetable who can bust through hard pans (think underground crusts) that defeat most plants, breaking up and aerating deep soil and easing compaction issues. They can be sown with a green manure as a soil improver.
Daikon for eating grow best in a rich deep soil, as for European radish, for the tastiest flavour and texture. Tillage daikon which aren’t intended to be eaten by humans can be grown in any old tired soil to help it rejuvenate.
On that note, radish of any variety can be grown as a biofumigant for your soil, helping to deter various unwanted nematodes and plant pathogens who live in the soil. For the most benefit the radish does need to be left in the ground to rot rather than ending up on your plate.
Big thanks to:
Camilla from Autarky Farm
Carole & Phil Helman, Nick Radford, John Hodgkinson, Jeff Holmes, Tim Hill, Pete Bufo
Supported by Bellingen Shire Council via the Bellingen Shire Disaster Recovery and Resilience Grant Program Funding
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