Vegetable · Brassicaceae
Rutabaga
Brassica napus subsp. rapifera
Sow it in summer, let the first hard frosts sweeten the roots, and rutabaga rewards you with a long-keeping fall harvest.
Full sun
Every 3–7 days
41–77°F · 5–25°C
90–100 days
Overview
Rutabaga is a cool-season root crop in the cabbage family, grown for the heavy, yellow-fleshed root that swells just at the soil line. It most likely began as a cross between a turnip and a wild cabbage, and it has fed northern kitchens and winter livestock for centuries. Gardeners also know it as the swede or Swedish turnip, and it thrives where summers stay mild and falls turn cold.
What sets rutabaga apart is patience. It needs a long, cool growing season of around 90 to 100 days, far more than a quick turnip, and it does its best work as the weather cools toward fall. The dense roots store for months in a cool cellar, which is why it earned its place as a staple long before refrigeration.
It asks little once it's in the ground. Give it deep, loose soil, steady moisture, and room to size up, then let the frost do the finishing. A few hard freezes turn the starch to sugar, and the root you dig in late fall tastes far sweeter than one pulled too early.
Care
The short version: full sun and deep, loose, well-drained soil, with about an inch of water a week to keep the roots from turning woody. Sow in summer, thin the seedlings to 8 inches apart, and harvest in fall after a hard frost or two.
Light
Rutabaga grows best in full sun, which means roughly 6 or more hours of direct light a day. It will tolerate a little partial shade, but the roots size up slowest and stay smallest where the light runs short.
Water
Aim for steady, even moisture, about an inch of water a week, especially as the roots are bulking up. Let the bed swing between bone dry and soaked and you'll get woody, cracked, bitter roots instead of sweet ones.
Soil
Plant in deep, loose, fertile loam that drains well and holds plenty of organic matter, with the stones cleared out so the roots can run straight down. A pH of 6.0 to 7.0 suits it, and keeping near the top of that range also helps hold clubroot at bay.
Temperature
This is a cool-weather crop that works between 41°F and 77°F (5°C to 25°C) and grows sweetest as the season cools. Heat makes the roots tough and sharp, while the frosts of fall are what turn the starch to sugar.
Humidity
Ordinary outdoor humidity is all it asks, so there's no number to chase. What matters more is steady soil moisture and good airflow around the foliage to keep leaf diseases from getting a foothold.
Feeding
Side-dress with nitrogen, such as calcium nitrate or a balanced fertilizer, about 3 to 4 weeks after planting to push leafy growth before the roots fill out. Rich soil with compost worked in beforehand carries much of the load.
Pruning
There's no real pruning to do here. Just thin the seedlings to about 8 inches apart so each root has room to size up, and pull off any diseased leaves you spot along the way.
Size & spacing
Plants reach about 12 to 18 inches (30 to 45 cm) tall in leaf, while the swollen root sits at the soil line. Give each one roughly 8 inches (20 cm) of space so the roots can grow full and round.
When to plant
Rutabaga is a fall crop that you plant in the warmth of summer and harvest into the cold. Direct sow in late spring through mid-summer, give it the long cool stretch it needs to mature, and dig the roots after one or more hard frosts have sweetened them.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Direct sow in late spring to early summer (late May to early June in northern gardens; mid-summer to early fall in the South) for a fall harvest
- Harvest: Harvest in fall after one or more hard frosts, which sweetens the roots
Hardiness
USDA hardiness zones: 3–9
Temperature: down to -40°C
Troubleshooting
Most rutabaga trouble happens out of sight, down in the root or among the young seedlings. Learn to read the early signs above ground and you can step in before a soil pest or disease ruins the crop. Match what you see below, then act while it still helps.
Brown tunnels boring through the root and wilting outer leaves
This is the work of the cabbage maggot, whose larvae chew channels through the root near the crown. Lift and destroy any infested roots rather than composting them. Cover the bed with a floating row cover at sowing and keep brassicas off the same ground in back-to-back years.
Fix:
- Remove and destroy infested roots
- Avoid planting brassicas in the same bed in successive years
Stunted plants with swollen, club-shaped roots
Swollen, distorted roots and midday wilting point to clubroot, a soil-borne disease that lingers for years once it arrives. There is no cure, so pull infected plants and bin them rather than composting. Keep the soil pH near 7.0, improve drainage, and rotate well away from cabbage-family crops.
Fix:
- Remove and destroy infected plants
- Do not compost infected material
Tiny shot-holes peppering the young leaves
Those little round holes are flea beetle damage, and the beetles hit hardest in warm, dry weather while plants are still small. Tap the foliage and you'll see tiny black beetles spring away. Drape a row cover over the seedlings from the day they emerge and keep them watered so they grow faster than the beetles can chew.
Fix:
- Cover seedlings with row cover
- Keep plants well watered and vigorous to outgrow damage
Brown, watery core inside an otherwise normal root
A grey-brown, corky center with a bitter taste is brown heart, caused by a shortage of boron in the soil. Cut a root open and the outside can look fine while the core has broken down. Test the soil before adding any boron, since it turns toxic in excess, and keep watering even on lighter ground.
Fix:
- Apply boron-containing fertilizer only per a soil test
- Maintain even soil moisture
Toxicity
Rutabaga is a food crop through and through, and every part of it is safe for people and animals alike. The roots and leafy tops have long been eaten and fed to livestock, so there's nothing here to worry about beyond ordinary moderation.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cooked or raw, rutabaga is safe for cats, though most show little interest in it. A small nibble of the root or a leaf does no harm.
Dogs None
Plain rutabaga is a fine treat for dogs, and many enjoy a cooked piece. Keep portions modest so the extra fiber doesn't upset a sensitive stomach.
Horses Safe
Horses can eat rutabaga without trouble. Slice it into small chunks rather than offering a whole root, which is easy to choke on.
Rabbits Safe
Both the root and the leafy tops are safe for rabbits as part of a varied diet. Introduce any new vegetable slowly to let the gut adjust.
Livestock Safe
Rutabaga has long been grown as winter feed for cattle and sheep, roots and tops alike. Grazing heavily on the raw brassica day after day can press on thyroid function through its natural goitrogens, so balance it with other forage.
Birds Safe
Chickens and other backyard birds happily peck at the root and greens with no ill effect. Chop it small so it's easy to manage.
People Safe
Rutabaga is a wholesome kitchen vegetable, good roasted, mashed, or in a stew. The roots and young leaves are both edible and safe to eat.
Like other brassicas, rutabaga contains glucosinolate goitrogens; very large raw quantities may affect thyroid function, so it is best fed in moderation and cooked.
Varieties
Only a handful of rutabaga varieties turn up in most seed catalogs, and they're more alike than different. These are the ones worth knowing by name.
American Purple Top
The most widely grown standard, with globe-shaped roots that wear purple shoulders over yellow flesh that turns orange once cooked.
Laurentian
A uniform purple-top type whose fine-grained, sweet yellow flesh makes it a favorite for fall storage.
Joan
An early, smooth-skinned purple-top variety that carries useful tolerance to clubroot.
How to propagate
Rutabaga is grown from seed and only from seed, sown right where it will mature. It resents transplanting, so there is no shortcut worth taking here.
SeedEasy
Direct sow outdoors in late spring to mid-summer for a fall crop · Seedlings emerge in 1 to 2 weeks; roots mature in about 90 to 100 days
Sow rutabaga straight into the garden, dropping seed about a quarter to half an inch deep in late spring or mid-summer for a fall crop. The seedlings come up within a week or two, and you thin them to roughly 8 inches apart so the roots have room to swell to full size over the next 90 to 100 days. Skip the transplanting, since rutabaga resents being moved and does far better sown where it will grow.
Myths
Rutabagas and turnips are the same vegetable.
They belong to different species and behave differently in the garden. Rutabaga is the larger, yellow-fleshed, sweeter root that wants a long cool season, while turnip is a faster, smaller, white-fleshed crop you can pull in weeks.
Harvest rutabagas before frost to keep them from spoiling.
Frost is the best thing that can happen to them. A hard freeze or two turns the root's starch into sugar, so the flavor improves after frost, and the best harvest comes once those cold nights have done their work.