Turnips

Brassica rapa

by Master Gardener Susan Shaw

Turnips (Brassica rapa) have been grown for over 4000 years and originated in Northern Europe. While the Urban Dictionary states that the word “turnip” refers to limited intelligence, it is the intelligent person who grows turnips. They are low-calorie, nutritious and, when properly cultivated and harvested, delicious.

The turnip is a rounded, cool-weather root vegetable with an edible bulb and greens. While it is a biennial, it is grown as an annual. Root colors can be white or have lavender shoulders with white bottoms. ‘De Milan’ and ‘Purple Top’ are two recommended varieties that are bi-colored and have white bottoms. I highly recommend ‘Tokyo,’ a Japanese turnip variety that is white and radish-sized. Its bulb is mild, sweet and juicy, and its greens are mild. Because it matures earlier, less days of watering are required. This makes ‘Tokyo’ a good choice when limited precipitation is a concern.

In Sonoma County, turnips can be seeded in the February through March for a spring/early summer harvest or in August through September for a fall/winter crop. Plant turnips in full sun in loose cultivated soil; sow the seeds 1/4- to 1/2-inch deep and one-inch apart. The seeds will germinate in four to seven days. Thin to four- to six-inches apart when seedlings are about two-inches high. The home garden that has been amended with an adequate amount of aged compost will provide a nutritious environment for the turnip’s life. While it is maturing, be cautious about applying too much nitrogen as it will encourage excessive foliage and cause misshapen roots.

Some people feel that the taste of turnips is too strong or bitter. This means that they have not had a properly cultivated turnip. Consistent water will insure tasty and mild-flavored turnips – the drier the soil the most robust the flavor of the turnips. And, there are two other important rules when growing turnips: never let them get too big and never eat them when they are old.

Turnips are frost-hardy but they may be injured if subjected to extended periods below 30 degrees. Generally, Sonoma County winters are mild. But frost cloth may be necessary if freezing weather is predicted.

Caterpillars are a frequent pest of Brassica genus crops (turnips, cabbage, cauliflower and broccoli, among others). Row covers will help prevent or lessen this problem. To avoid soil-borne diseases, do not plant Brassicas in the same area in consecutive years.

Greens from the turnips can be harvested before the bulbs mature. The roots should be harvested at two- to three-inches wide, about 50 to 75 days after sowing the seeds (Japanese turnips have 30 to 60 days-to-maturity). Turnips should not be left in the ground because they will become woody. Topped turnips can be stored in a cool dark place for up to three months if left unwashed, or washed and stored in the refrigerator up to two weeks.

According to the USDA, a 1/2-cup serving of turnips has 20 calories, no fat, 2 grams of fiber and 15 percent of the daily recommended amount of vitamin C. The bulb and greens of the Japanese turnip ‘Tokyo’ can be eaten raw in salads. Mature rose or purple topped varieties can be cooked like potatoes or carrots in soups, stews, mashed, alone or combined with other root vegetables. If serving turnips as a stand-alone vegetable, try adding some olive oil and seasoning them with chopped herbs (e.g., rosemary, thyme or basil) or ground spices (e.g., cinnamon, ginger or cumin).