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 are in the Brassicaceae or 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 bulbs are generally either white or yellow, with the part of the bulb 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.
|Botanical Name||Brassica rapa|
|Mature Size||12–18 inches in height, 6 to 8 inches wide|
|Sun Exposure||Full sun to part-shade|
|Soil Type||Sandy, well-draining soil|
|Native Area||Middle and Eastern Asia|
How to Grow Turnips
Turnips are a versatile crop. Like beets, they can be grown for greens or for the bulb. They grow fairly quickly, maturing in about 2 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.
Turnips are direct seeded in the garden either in early spring or in the fall, about 70 days before your first frost date. Plant seeds about 1/2-inch deep.
When the plants are three to four inches tall, thin them to 2 to 4 inches apart. You can use the thinned out plants as greens.
For a prolonged harvest, succession plant every 10–14 days.
Turnips thrive in full sun but can make do with partial 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.
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 your seeds.
Turnip greens can be harvested any time after they reach four inches tall. If you don't harm the top of the bulb, the greens will continue to regrow. The bulbs are best when they are small and tender, around 2 or 3 inches in diameter. Older turnips can get tough or pithy. 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 roasted. Older, woodier turnips can still be used for mashing or for soups and stews.
If you are going to store your 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.
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 in the same spot for more than two years in a row. For 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.
Varieties of Turnip
- 'Alltop': Bred for its greens; fast-growing and will re-sprout quickly after harvest (35 days)
- 'Golden Ball': Small, sweet yellow bulbs with a faint almond taste (60 days)
- 'Purple Top White Globe': Most popular variety because it grows so well (55 days)
- 'Scarlet Queen': Bright red outside, white inside; slow to turn pithy (45 days)
- 'Shogoin': Grown for its broad, mild greens, but the bulb is also good (45 days)
- 'Tokyo Cross': AAS winner; very uniform, quick growing and slow to turn pithy (35 days)