Kohlrabi: a forgotten tuber | News, Sports, Employment

Hello Mid-Ohio Valley gardeners and farmers! The heat continues into August as we continue to experience dry conditions with little rain.

Extremely hot and dry weather is affecting crops and gardens here in the Valley. Even for those gardeners who water their gardens, many plants will suffer from the extreme heat. In some cases, plants will wilt by midday simply because the leaves are losing moisture faster than the root system can absorb water.

Drought stress has its most severe effects at or near the time of flowering or pollination in most fruiting vegetable crops, such as sweet corn, tomatoes, peppers, and beans. Vegetables that have roots or leaves need an even supply of water throughout the growing season.

Tomatoes, peppers, melons, squash, cucumbers and green beans often lose their flowers without setting fruit when daytime temperatures exceed 90°F (32°C), even if they are not drought stressed. There is not much you can do except wait for cooler temperatures to prevail. As more favorable conditions return, the plants should resume normal fruit production.

Sweet corn is also likely to have trouble filling ears in extremely hot weather. Unfortunately, you only get one flush of flowering with corn. So if it turns out your plants are shedding pollen when the weather is stressful, you can expect poor ear filling.

Of course, watering will help, but adding additional organic mulch, such as straw, hay, and grass clippings, can help mitigate drought stress. Organic mulches keep the soil cool and reduce weed growth, as well as evaporation of soil moisture.

Even though we are sweating in the August heat now, fall is right around the corner. Fall is a great time to plant turnips, kale, and rutabagas. Many of you may not be familiar with rutabagas (Brassica napus). Rutabagas are a cool-season root crop in the Brassica family and are, in many ways, a larger version of the turnip (Brassica rapa).

However, rutabagas tend to be slightly larger, sweeter, and less strongly flavored than the smaller turnips. Both grow well in cool climates and can be very productive. Like other root vegetables, quality can be poor when either of these crops is grown in hot climates or becomes too large and fibrous.

Rutabagas have an interesting history here in the United States. They gained popularity among farmers from an article written by William Cobbett and published in the American Farmer magazine. Beginning in the early 1820s, the magazine distributed rutabaga seeds to curious farmers throughout the United States.

Askov, Minnesota (population 364) was once called the rutabaga capital of the U.S. and still holds the Rutabaga Fair and Festival every fourth week in August. Rutabaga sausage is served alongside traditional Danish Aebleskiver (pancakes). Nursery owner Ludvig Mosbaek sent rutabaga seeds from Denmark in 1909.

Rutabagas were once very popular in West Virginia. They were originally marketed as winter feed for livestock, but were widely grown for human consumption, including in meat stews or mashed with milk or cream. The Appalachian Mountain prairies of West Virginia were popular locations for growing potatoes and rutabagas in the late 19th and early 20th centuries.

Rutabaga comes from rotabagge, the Swedish name for the plant meaning “loose root.” This cross between cabbage and turnip is sometimes called rutabaga or kohlrabi. In West Virginia, it is also known as Hanover turnip. Some sources mention Hanover salad as a subspecies of rutabaga.

Rutabagas are typically tougher and denser than turnips, ranging in shape from oval to round or triangular, with yellowish to brown skin and cream-orange flesh. Rutabaga leaves are blue-green, thick and smooth. Roots are typically more elongated than turnips and have a thick, leafy neck.

Both rutabagas and turnips thrive in cold climates and can be very productive.

However, rutabagas require a longer growing season (90 days or more) compared to turnips (45-60 days). Turnips are harvested at a smaller size (baseball size) compared to a baseball size or larger for rutabagas.

Rutabagas are sweeter and have orange flesh compared to the spicy, mustard-like flavor of the white-fleshed turnip.

Rutabagas are usually tougher and denser than turnips.

The shape of the rutabaga varies from oval, round or triangular, with yellowish to brown skin and orange-cream flesh. The more familiar turnip is smaller and rounder, with purple and white skin and white flesh. The quality of both can be poor when grown in warm climates or they become too large and fibrous.

Many traditional varieties of kohlrabi were grown, including: “Mariana,” “Navone,” “American Purple Top Yellow” “Nadmorska” “Laurentian” and “Wilhelmsburg.” This forgotten root is larger and sweeter, with orange flesh, compared to the mustard-like flavor of the smaller, white-fleshed turnip.

Purple Top and Laurentian are widely available from commercial seed companies.

Moderately deep, very fertile, well-drained soil with a pH of 6.2 to 6.8 is best for growing rutabagas. Rutabagas can be planted in rows 14 to 18 inches apart. Work the soil well to form a good seed bed and incorporate fertilizer well. Plant seeds 1/2 inch deep with about 4 inches between plants. Initial planting can be closer together and then plants can be thinned to 4-inch spacing.

Aphids, flea beetles, root maggots and wireworms are serious pests. Root maggots and wireworms attack roots and may require appropriate soil application of insecticides prior to planting to control them. Aphids and flea beetles damage leaves and a spray programme may be necessary to control them.

Harvest rutabagas after they have been exposed to several light frosts. This will enhance the sweetness and flavour of the roots. Roots should be 10-12cm in diameter. Cut the foliage back to 2.5cm from the crown.

Rutabagas should be cooked and can replace potatoes in almost all recipes. The following is a recipe from Theresa C. Brown’s book Modern Domestic Cookery (1871).

Mashed rutabagas. Remove the skin, drop them into boiling water cut into slices, simmer until tender, remove, squeeze out the water with a plate, mash and return to a clean, hot saucepan, mix with a large spoonful of butter, season with pepper and salt to taste.

Preparation methods include roasting, baking, or steaming. Roasting these vegetables brings out their natural sweetness.

The green tops of both turnips and rutabagas are edible.

Please contact me at the Wood County WVU Extension Office at 304-424-1960 or email me at [email protected] if you have questions.

Until next time, good luck and happy gardening!