There is an old Missouri saying, “On the twenty-fifth of July, sow your turnips, wet or dry.” This local adage vaulted into the national spotlight during the presidency of Missouri native Harry S. Truman. Evidently, the congressional session of 1948 was a particularly rancorous one, with the GOP-dominated Congress refusing to pass any of President Truman’s initiatives. In reprisal, President Truman called a two-week special session to deal with matters Congress had refused to address before adjourning for the summer. The President proposed that it should begin on “what we in Missouri call Turnip Day—July 25th”
The tactic did not work since Congress still refused to pass any of President Truman’s initiatives in what historians refer to as the Turnip Day Session. However, it did bring to the attention of the American public that, at least in Missouri, late July is a good time to plant turnips.
Turnip (Brassica rapa var. rapa) is a member of the Brassicaceae (Mustard) family and has been cultivated since prehistoric times. Its common name is an old compound of the word neep, which was used by ancients as a name for the vegetable now called rutabaga (Brassica napus). Indeed, turnip and rutabaga are closely related, with the latter thought to be a chance hybrid between cabbage and turnip.
Turnip was well-established as a crop during the Greek and Roman eras. Roman naturalist and philosopher Pliny the Elder considered turnip to be a very important food source, ranking it just behind cereal grains and beans. He also mentioned its value as “animal fodder”, a use for turnip that still is practiced today. Its use a food for animals as well as the poor delayed its widespread acceptance by the upper class. By the 18th century, however, turnip was grown throughout the cooler climes of Europe and became an integral part of its food chain and culture.
French explorer Jacques Cartier is credited with introducing turnip to America when he planted it in what is now Canada in 1541. The colonists are known to have grown it in Virginia as early as 1609 and later in other (now) New England states. Native Americans were quick to adopt its culture from the colonists and grew it widely.
Turnip is a biennial grown both for its edible storage root as well as its leaves. In nature, the plant spends its first year growing and enlarging its root. During its second year, the plant flowers, produces seed and dies.
Because of its affinity for cool temperatures, turnip is an ideal fall garden crop. The cool days of late summer and fall are ideal for root development. Hot temperatures tend to make turnip roots fibrous and pungent. In the garden, turnip often is planted in space vacated when earlier crops such as peas, spinach or onions have been harvested. It also is feasible to plant turnip as a companion with corn. The seedlings will get some shade from the larger corn plants but will develop rapidly after the corn has been harvested and stalks removed from the garden.
Like most root crops, turnip prefers a fairly light soil. Heavy clay soils are less desirable and tend to inhibit root development and cause poor root shape. For best seed germination, prepare a seedbed that is fine and smooth. If a crop had been growing in the space in which turnips are to be seeded, remove it completely. Also, remove all debris and weeds. If the soil is dry, water the space to be seeded a day or two before digging or tilling.
Adequate fertility is import for turnip, especially in its early development. Apply a garden fertilizer (e.g. 5-10-5) at the rate of about one pound for each 100 square feet of area to be planted. If the previous crop was very productive, this additional fertilizer might not be needed. In this sense, turnip is a good “cleanup” crop to make full use of fertilizer applied to the garden during a growing season.
Turnip seeds may be broadcast over the prepared soil or planted in rows 12 to 15 inches apart. Lightly cover the seeds after planting. If seeds are broadcast over the soil’s surface, a light raking after planting usually is sufficient to cover them.
In spite of the above-mentioned saying to sow turnips “wet or dry” daily light watering is advised until seeds have germinated and become established. Moisture will not only aid seed germination, it will tend to cool the seedlings at a time when the weather is still a bit warm for turnip’s liking.
Turnip plantings are subject to attack by several insect pests. Flea beetle, aphid, root maggots and wireworms are the most problematic. Turnip diseases include white spot, white rust, downy mildew, anthracnose and alternaria leaf spot, all of which are caused by fungi. Bacterial black rot and leaf spot as well as mosaic virus can be problematic also. Crop rotation within the garden is helpful in managing turnip diseases.
Harvesting and storage of turnip varies somewhat with intended use. Some are harvested by pulling both leaves and roots and binding them together in a bunch. If this method is used, a root diameter of about two inches is quite common. For turnips that will be topped and harvested for their root only, it is best to wait until roots have achieved a diameter of at least three inches. Turnip is relatively cold hard and can withstand freezing temperatures. However, harvest should be accomplished before the soil freezes. The latter tends to crack the roots which then decay in the soil.
Turnip roots are best stored at temperatures at or just above freezing (32-35° F.). Refrigerators are great for storage, if space is available. To store larger amounts of turnip roots, consider an unheated basement or outdoor pit storage. The latter consists of burying a large, water-proof container (e.g. 55 gallon plastic drum) in a semi-horizontal or slanted position. Put turnip roots in the container and place the lid on lightly to allow for air circulation. Finally, cover the storage container with a generous layer of straw held in place with a thin layer of soil
There are a number of turnip varieties well-suited for Missouri conditions. ‘Purple Top White Globe’ one of the best and forms a root shaped like a flattened globe with a purple top and creamy-white interior. It normally produces edible (four-inch) roots about 60 days after seeding. For an earlier harvest, ‘Tokyo Cross’ is a faster-maturing variety that produces two-inch roots in a mere 30 days. Contrastingly, ‘Golden Ball’ requires 70 days to produce golden-yellow roots that are sweet and flavorful.
REVISED: September 29, 2015