Turnip (Brassica rapa var. rapa)
The exact origin of turnips cannot be determined by the archeological record, but it appears that they were established as food crops in ancient Greece and Rome. The closely related radishes and mustards appear to have originated in West Asia/Eastern Europe, so it’s reasonable to suspect that turnips were domesticated in that general area. There is a long tradition of growing turnips for feeding livestock, but human consumption was certainly early as well. Pliny the Elder wrote about turnips that they were the most important crop “directly after cereals, or at all events after the bean, since its utility surpasses that of any other plant.”
Prior to the potato’s arrival from the New World, turnip was the root-crop of choice for cool, wet soils, so many northern European cultures have significant relationships with this vegetable. In 1730, the British parliamentarian Charles Townshend imported turnips from Holland in order to see if his livestock could survive winter eating turnips alone. Hay was expensive to produce and store over winter, so at that time, many farmers slaughtered all their livestock in the fall. Turnips, which are easy to grow and store for long periods turned out to be just the thing, fattening cattle throughout the winter – and this was something of an agricultural revolution in its way. It meant that beef cattle and other livestock could be slaughtered over a much longer period, as needed, rather than by the demands of the calendar. Townshend also popularized four-field crop rotation in Britain, which was a boon to all farmers.
Turnips for human consumption may be grown for either their bulbous roots, or their nutritious greens. The root grows at ground level, with as much as two thirds of it protruding above the soil surface. This part of the turnip is, of course, exposed to sunlight, and may mature to deep purple, red, or green, depending on the variety. The portion below ground and the entire interior of the root is white.
Turnip leaves (or greens, or “turnip tops” in the UK) are very similar in flavour to mustard greens, with a bit of spice to them. Select the smallest, youngest leaves for the best flavour, as more mature leaves tend to be bitter. This bitterness can be removed by boiling once, and then a second time in fresh water. Turnip roots have little nutritional value aside from being high in dietary fibre and vitamin C. The greens, however, contain significant concentrations of vitamins A, B, C, and K, as well as calcium and lutein, an antioxidant.
Räbenlicht is observed in Mid-November in many German and Swiss towns. It is a celebration of the passing seasons, and the event is all about turnips. Masses of turnips are hollowed out and then carved shallowly through the skin. In the town of Richterswil, on the southern bank of Lake Zurich, they call the event Räbechilbi, and carve upwards of 30 tons of turnips. Everyone gets involved and each lantern is lit with its own candle. Thousands of hand-carved, individually lit turnips line the streets and adorn houses and shop windows, and the street lights are switched off. All these turnips are grown especially for the festival, and not eaten. Instead they are turned into a giant, glowing thing of beauty enjoyed by the whole community.
How to Grow Turnips:
Difficulty: Easy to grow in the garden, but not suitable for containers.
Timing: Direct sow April through August.
Sowing: Sow thinly 1cm (½”) deep in rows 30-45cm (12-18”) apart. Thin to 5cm (2”) apart.
Soil: Moderate to heavy feeders. Best in rich, loamy soil amended with composted manure. Add 4L (1 US gallon) of complete organic fertilizer for 10 sq m (100 sq ft) of bed for background fertility. Lime beds in fall, before planting, to bring the pH to 6.0 — 6.8.
Growing: Loose soil and regular watering will give you maximum fast growth of these plants. Do not let them sit in the ground any longer than necessary, because the root maggots will destroy them. Plant your turnip seeds in a sunny area of your garden. Sow short rows frequently, as you would radishes.
Harvest: Pull turnips from the ground as soon as they have sized up adequately.
Seed info Germination temperature is 45 to 85 F, but will germinate at soil temperatures as low 40 F. Optimal soil temperature for germination: 25-35ºC (68-95ºF). At least 80% of seeds will germinate in optimal conditions. Usual seed life: 4 years.
Growing for seed: Turnips are pollinated by insects and will cross-pollinate with all other turnips, plus all members of Brassica rapa – Chinese cabbage, mustards, etc… To ensure genetic purity when growing for seed, isolate each variety by 2km (1 mile).Pests & Disease: Cabbage root maggot (Delia radicum) is a little fly that lays her eggs on the soil where the stems of all brassicas emerge from the ground. Using a floating row cover will protect directly-seeded crops. Expect to lose 20-30% of your crop without this protection. Transplants of the bigger plants can be protected with nematodes or individual plants can be protected with a square of cardboard or old rug fitted snuggly against the stem.