A winter radish with an unmistakable presence — coal-black skin, crisp white flesh and just the right amount of heat.
About the variety. Traditional variety with white, opaque flesh that is crisp, tender and pleasantly pungent. Compact plants of 15–20 cm. The flowers are edible and the variety adapts well to container growing.
Indicative windows; adjust them to your local climate.
Edible flower
Suitable for pots
Frost hardy
Direct sowing
Growing guide
How to grow radish nero tondo d'inverno?
A step-by-step growing guide, from sowing to harvest.
Sowing
Always sow direct, one to one and a half centimetres deep in rows, and thin early and wide, because the root reaches the size of a small apple. Germination takes three to five days. Sowing too thickly and not thinning is the direct cause of radishes that make nothing but leaves. Sow once in late summer, in August or September: it is a single autumn and winter harvest, not a successional sowing. At about 20 centimetres tall, this variety grows well in a pot twenty centimetres deep with drainage holes. Use a pot at least twenty five centimetres deep with drainage holes, and expect to water more often, because a pot dries out far faster than open ground.
Soil
It wants loose, fine, stone free and moist soil at a pH between 6.0 and 7.0. No manure and no nitrogen feeding, which give leaves instead of root. Compacted soil gives deformed hard roots. A little mature sieved compost worked in before sowing is enough for the whole cycle.
Climate
It is a winter radish, with a longer cycle than spring radishes, and grows well between 10 °C and 20 °C. Sown in late summer, it forms its root as the days shorten and autumn cools, which gives dense flesh and a hot but balanced flavour. Spring sowings almost always bolt because of the long days, so do not make them. It takes light frost and in the south can stay in the ground through much of the winter. On the Portuguese coast and in southern Spain sow from August to September and harvest from October to January. Inland in Portugal and Spain sow in August, so the root is formed before the hard frosts, and cover with straw if the cold bites. In France and Germany sow from mid July to mid August and harvest in October and November, before the ground freezes. In Italy follow the Iberian calendar in the centre and south and the French one in the north.
Fertilisation
Do not use fresh manure or strong nitrogen feeding: that gives forked, hairy and tasteless roots. Use a bed that was composted for the previous crop and top up potassium only, with sieved wood ash, which improves sweetness and keeping quality. In such a short cycle there is no time to feed during the crop: everything the plant needs must be in the soil before sowing.
Watering
Water often and consistently: it is the key to this crop. Irregular watering gives split, hollow and very hot roots. Soil kept slightly moist at all times produces dense, tender and milder roots.
Weed control
Hoe often and always shallowly, because the roots are short, near the surface and break easily. The best method is to prepare the bed two or three weeks in advance, let the first flush of weeds germinate, remove it and only then sow: that gives you a decisive head start. A thin layer of sieved compost between the rows greatly reduces later work.
Pest control
Flea beetle, a small jumping beetle, riddles young leaves with round holes in hot dry weather: keep the soil moist and cover with fine mesh from sowing. Cabbage white caterpillars and diamondback moth eat the leaves: apply Bacillus thuringiensis while the caterpillars are small. Cabbage root fly lays at the collar and the larva destroys the root: a cardboard or felt collar around the stem stops the egg laying. Grey cabbage aphid forms waxy colonies on the shoots and is dealt with using potassium soap. A fine insect mesh put on at sowing solves practically all of these at once.
Diseases
Being a short cycle crop it suffers few diseases. The main risks are root rot in waterlogged soil and clubroot if the family is repeated in the same bed. Rotate with cabbages, turnips and rocket, and do not sow in poorly drained ground. In cool damp weather downy mildew or white blister sometimes appears on the leaves: space well and water in the morning so the foliage dries quickly.
Harvest
Harvest from October onwards, when the root is the size of a small apple and still firm. Unlike spring radishes it does not go hollow within days: it can stay in the ground for weeks, lifted as needed, until the hard frosts arrive. Lift with the soil damp, pulling by the leaves or with a fork if the root is deep. To store, cut the tops off close and put the roots in damp sand in a cool place, where they last several months. The reference colour is black skin with opaque white flesh, and that is what tells you it is ready.
