How to Grow a Rutabaga

Garden bed

A garden bed suits most growers because rutabaga sends roots down 12 inches or more, and a bed gives the plant plenty of room and easy access to soil moisture. The bed needs at least 12 inches of loose, stone-free soil for the roots to swell into a smooth shape. Heavy clay or rocky soil produces forked, knobby roots, so amend with several inches of compost before sowing.

Pot

A pot works when the yard soil is heavy or shallow, or when garden space is tight. Use a container at least 12 inches deep and 12 inches across per plant, with drainage holes at the base. Fill with a loose vegetable potting mix rather than dense garden soil.

Container roots dry out faster and the plant needs more attentive watering through summer. Plan on checking soil moisture every couple of days through the warmest weeks.

Sun

Full sun, with at least 6 hours of direct light each day. Less sun produces small misshapen roots and leggy tops. In hot southern climates, light afternoon shade through early fall protects the leaves while the roots finish swelling.

Drainage

Rutabaga needs well-drained soil. Standing water rots the swelling root within days. Dig a one-foot test hole and fill with water. If it drains within a couple of hours, the spot works. If water sits overnight, build a raised bed 8 to 12 inches above grade so the root zone stays out of the wet layer.

Soil

Loose loamy soil enriched with compost is ideal. Avoid fresh manure or high-nitrogen amendments that push leafy growth at the expense of root size. Remove rocks and large clods from the top foot of soil so the root can swell into a smooth round shape rather than forking around obstacles.

Crop rotation

Rotate rutabaga out of beds that grew other cabbage-family crops in the last two years. Cabbage, broccoli, kale, turnip, and radish share the same soil-borne diseases and pests, and back-to-back planting builds up clubroot and cabbage root maggot in the bed.

Watering

Water deeply once a week, applying about an inch of water at the base of the plants. Soaker hoses or drip lines work better than overhead sprinklers because wet leaves invite fungal disease. In hot dry stretches, increase to twice a week so the soil never dries out completely.

Consistent moisture is the key to smooth round roots. Wet-dry-wet swings cause the swelling root to crack across the shoulders and split open down the side. A two-to-three-inch mulch layer evens out the moisture between waterings.

Feeding

If the bed was amended with compost at planting, rutabaga generally needs no additional feeding. On lean soils, a single side dressing of compost or a low-nitrogen balanced fertilizer a few weeks after thinning supports steady root development.

Avoid high-nitrogen fertilizers and fresh manure. Excess nitrogen produces huge leafy tops and small woody roots. Stop all feeding once the root starts to swell visibly above the soil line.

Weeding

Weed by hand or with a shallow hoe through the first month after thinning. Once the rutabaga leaves close in over the row, the canopy shades out most weeds on its own. Avoid cultivating deeper than an inch near the plants, since deep cultivation cuts feeder roots and slows root development.

Removing damaged leaves

Snap off any badly chewed, yellowing, or rotting leaves at the base of the plant. Discard them away from the bed to break pest and disease cycles. Healthy plants generally hold a full canopy of leaves through the season.

Hilling the shoulders

As the roots swell, the top of the rutabaga pushes above the soil line and turns green or purple where exposed to sun. Pull a thin layer of soil or mulch over the exposed shoulders to keep the skin tender and the flavor mild. Skipping this step does not ruin the harvest, but the green tops are tougher and slightly bitter.

When it's ready

Look for roots roughly the size of a baseball, with about 3 to 5 inches of shoulder visible above the soil. The skin should be firm and the top growth healthy. Smaller roots stay tender but yield less per plant. Roots much larger than a softball can turn woody and fibrous.

Plan the first big harvest after one or two frosts in the high 20s. The frost-sweetened flavor is noticeably better than the flavor of an unfrosted root pulled before the cold weather sets in.

Picking and storing

Grasp the base of the leafy top and pull straight up. If the root resists, loosen the soil around it with a fork before lifting. Twist or cut the leafy tops off about an inch above the crown, brush soil off the root, and avoid washing until you are ready to use it.

Store rutabaga in a cool humid spot at around 32 to 40 degrees, such as a refrigerator crisper or an unheated basement. Roots keep for 2 to 4 months under good conditions. A coating of food-grade wax extends storage for the larger fall harvest.

Leafy tops

The leafy tops are edible and taste similar to mild collards or kale. Cook them like any other cooking green, especially while they are young and tender. Older outer leaves can turn fibrous and are usually composted.

Roots are small and woody

Almost always caused by overcrowding, too little sun, or planting too late in spring so the roots size up in summer heat. Thin to a true 6 to 8 inches between plants and sow for fall harvest rather than spring. Heat-stressed rutabaga turns bitter and woody no matter how long it stays in the ground.

Forked or knobby roots

The root grew around stones, clods, or compacted soil. Loosen the top 12 inches of soil before sowing and remove rocks. Fresh manure also causes forking and should be composted for a full season before going into the rutabaga bed.

Cracked or split roots

Caused by uneven watering, especially a heavy rain or deep soak after a dry stretch. Mulch the bed two to three inches deep and water consistently through summer so the root size grows steadily rather than in bursts.

Cabbage worms and loopers

Green caterpillars chewing ragged holes in the leaves, often with dark green droppings on the foliage. Hand-pick them in small gardens or spray with Bt (Bacillus thuringiensis), which kills caterpillars without harming bees or beneficial insects. Floating row cover from sowing through harvest keeps the moths off the plants entirely.

Flea beetles

Tiny black beetles that jump when disturbed, leaving the leaves peppered with shot-hole damage. Damage is mostly cosmetic on established plants but can stunt seedlings. Cover seedlings with row cover until the plants outgrow the threat, and dust the leaves with kaolin clay during peak pressure.

Cabbage root maggot

Wilting plants with white maggots tunneling into the root and crown, more common in spring sowings on cool wet soils. Use row cover at sowing or place cardboard collars around seedling stems. Rotate out of cabbage-family beds for two to three years if root maggots are a recurring issue.

Yellowing lower leaves

Either natural senescence on older outer leaves as the plant matures or a nitrogen shortage on lean soil. Snip yellowing leaves off and side-dress with compost. Widespread yellowing in young plants points to root maggot or clubroot, both of which warrant pulling and inspecting a plant to confirm.

Clubroot

Plants wilt during the day and recover at night, and pulling reveals swollen distorted roots with club-like growths instead of a smooth swelling root. The soil-borne disease persists for 7 or more years in infected beds. Pull and discard infected plants, raise the soil pH to 7.0 or higher with lime, and rotate out of cabbage-family crops in that bed for at least 4 years.

Powdery mildew on leaves

White powdery film on the foliage in late summer when nights turn humid. Improve airflow by keeping plants thinned and weeded. The leaves are not the harvest, so light mildew rarely affects yield. Heavy outbreaks respond to a horticultural oil spray or potassium bicarbonate.

Bolting in spring sowings

Spring-sown rutabagas occasionally bolt and form a flower stalk in midsummer heat, leaving a woody root behind. Sow in mid to late summer for a fall harvest instead. Bolted plants do not recover, so pull them once you see the flower stalk and use the space for a fast follow-up crop.