We are most familiar with the white and purple tennis ball-sized turnips commonly sold in grocery stores, but there is a good deal of variety beyond those, including small, tender radish-sized turnips. Turnips (Brassica rapa) are in the Brassicaceae (mustard) family and their edible green tops have a flavor similar to mustard greens.
Turnip leaves are light green and slightly hairy. They grow into an elongated oval, with toothed or wavy edges. Turnip roots are generally either white or yellow, with the part that protrudes above ground purple or green thanks to sun exposure. If allowed to bolt, turnip flowers are small and yellow. As with other Brassica plants, the four petals form a cross, which is why they are also referred to as cruciferous vegetables.
Turnips are normally planted from seeds either in early spring or in fall, at least 70 days before the first frost. They mature in about two months.
|Botanical Name||Brassica rapa|
|Plant Type||Annual vegetable|
|Mature Size||12–18 in. tall; 6- to 8-in. spread|
|Sun Exposure||Full sun to part shade|
|Soil Type||Sandy, well-draining|
|Soil pH||Slightly acidic (6.0–6.5)|
|Native Area||Europe, especially Mediterranean regions|
|Hardiness Zones||Annual plant; grown in zones 2 to 9|
How to Plant Turnips
Like beets, turnips are a versatile crop that can be grown for greens or for the roots. They grow fairly quickly, maturing in about two months, so you can get more than one harvest in a season. The bulbs form best in cool weather, around 60 degrees, so early spring and fall crops are favored.
Although nursery transplants may be available, most people plant turnips by direct-seeding them in the garden, either in early spring, or in the late summer or early fall, about 70 days before the first frost date. Plant seeds about 1/2 inch deep. When the plants are 3 to 4 inches tall, thin them to 2 to 4 inches apart. You can use the thinned out plants as edible greens.
For a prolonged harvest, succession plant every 10 to 14 days.
Turnips thrive in full sun but can make do with part shade.
At least 1 inch of water per week is vital for good root development. Turnips need to grow quickly, and regular water along with a rich soil, will help them do that. Dryer conditions make the roots more pungent, while uniform water makes for the best flavor.
Temperature and Humidity
Turnips grow best in the cool weather of spring and fall.
Since they grow so quickly, you shouldn't need to fertilize your plants. Just make sure the soil has plenty of organic matter in it before you sow the seeds.
- 'Alltop' is usually bred for its greens. This fast-growing cultivar (35 days) will re-sprout quickly after the greens are harvested.
- 'Golden Ball' has small, sweet yellow bulbs with a faint almond taste. It matures in 60 days.
- 'Purple Top White Globe' is the most popular of all varieties because it grows so well. It matures in 55 days.
- 'Scarlet Queen' is bright red outside, white inside, and is slow to turn pithy. It matures in 45 days.
- 'Shogoin' is usually grown for its broad, mild greens, but the root is also good. It matures in 45 days.
- 'Tokyo Cross' is an AAS winner—very uniform, quick-growing, and slow to turn pithy. It matures in only 35 days.
Turnip greens can be harvested any time after they reach 4 inches tall. If you don't harm the top of the root structure, the greens will continue to regrow. The roots are best to eat when they are small and tender, around 2 or 3 inches in diameter. Older turnips can get tough or pithy, as well as somewhat bitter. Fall planted turnips can be left in the ground and harvested into the winter, since they are no longer actively growing. A layer of mulch will help prevent freezing and the cold weather will sweeten their flavor.
Tender, new turnips can be eaten raw. They have some of the mature turnip tang, but slightly tempered. You can chop them into salads or wedge them for crudite. Larger turnips can be baked or used in stews, but like most root vegetables, they are fantastic when roasted. Older, woodier turnips can still be used for mashing or for soups and stews.
If you are going to store turnips, remove the leaves first or they will continue to draw energy and nutrients from the bulbs. Use the greens as soon as possible. The bulbs can be stored in the refrigerator or any cool, dark place for months.
Common Pests and Diseases
Turnips are prone to all the usual problems associated with growing Brassicas, including anthracnose, clubroot, leaf spot, scab, turnip mosaic virus, Rhizoctonia rot, root-knot, and white rust. The best way to prevent these diseases is to avoid planting any Brassica species in the same spot for more than two years in a row. If you have experienced clubroot, waiting six years to grow Brassicas in the same area is recommended.
Insect pests include turnip aphids and flea beetles, which damage the greens. Row covers can be used to keep them off the leaves. Root maggots and wireworms cause more of a problem because they damage the bulbs.