Vegetable · Brassicaceae
Rutabaga
Brassica napus subsp. rapifera
Get the seed down in summer, cheer the roots on through the cool weeks, and let a hard frost crank up their sweetness for a harvest that keeps and keeps.
Full sun
Every 3–7 days
41–77°F · 5–25°C
90–100 days
Overview
Rutabaga is a cool-season root in the cabbage family, and it grows a hefty, yellow-fleshed root that pushes right up to the soil line. It sprang most likely from a turnip crossed with a wild cabbage, and it has kept northern kitchens and winter animals going for centuries. Gardeners still swap it around as the swede or Swedish turnip, and it takes off wherever summers stay mild and fall turns good and cold.
The real fun with rutabaga is watching patience pay off. It runs on a long, cool season of around 90 to 100 days, far more than a speedy turnip, and it powers into its best growth as the weather cools toward fall. Stash the dense roots in a cool cellar and they hold for months, which is exactly why they earned staple status long before the fridge came along.
Best of all, it barely asks for anything once it takes hold. Hand it deep, loose soil, keep the water coming, and give it elbow room, then let the cold work its magic. A few hard freezes flip the starch to sugar, so the root you haul up in late fall tastes miles sweeter than one you rushed out of the ground early.
Care
The short version: hand rutabaga full sun and deep, loose, well-drained soil, and keep about an inch of water coming each week so the roots stay tender. Sow in summer, thin the seedlings to 8 inches apart, and dig in fall once a hard frost or two has done its thing.
Light
Rutabaga charges ahead in full sun, which really means about 6 or more hours of direct light a day. It puts up with a touch of partial shade, but the roots crawl along and stay small where the light runs thin, so hand it your brightest spot.
Water
Keep it evenly moist, around an inch of water a week, and stay on it while the roots are bulking up. Let the bed lurch from bone dry to soaked and you will end up with woody, cracked, bitter roots instead of the sweet ones you are after.
Soil
Set rutabaga into deep, loose, fertile loam that drains fast and holds loads of organic matter, with the stones cleared so the root can plunge straight down. A pH of 6.0 to 7.0 hits the mark, and edging toward the top of that range also keeps clubroot from muscling in.
Temperature
This crop thrives cool, cruising between 41°F and 77°F (5°C to 25°C) and growing sweeter the more the weather cools. Heat just leaves the roots tough and sharp, while fall's frosts are the payoff that flips the starch to sugar.
Humidity
Skip the humidity worries, since plain outdoor air suits it fine and there is no number to hit. What really counts is steady soil moisture and lively airflow around the leaves to shut leaf diseases out.
Feeding
Give it a side-dressing of nitrogen, calcium nitrate or a balanced fertilizer, about 3 to 4 weeks after planting to fire up leafy growth before the roots fill out. Work compost in first and that groundwork does much of the feeding for you.
Pruning
No pruning to chase here at all. Just thin the seedlings to about 8 inches apart so each root has room to bulk up round and full, and flick off any diseased leaves you spot on your rounds.
Size & spacing
In leaf the plants shoot up to about 12 to 18 inches (30 to 45 cm), while the swollen root sits right at the soil line. Hand each one roughly 8 inches (20 cm) of space and the roots pack on full, rounded size.
When to plant
Rutabaga plays a fun trick on the calendar: start it in summer heat and finish it in the cold. Direct sow from late spring right through mid-summer, hand it the long cool run it craves to size up, and hold off digging until one or more hard frosts have loaded the roots with sweetness.
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 sneaks in where you cannot see it, down in the root or among the tiny seedlings. Get sharp at reading the clues up top and you can jump on a soil pest or disease before it spoils your fun. Scan the symptoms below, find your match, and move fast while it still helps.
Brown tunnels boring through the root with wilting outer leaves
Tunnels snaking through the flesh near the crown, plus outer leaves that flop, spell cabbage maggot, whose larvae chew right into the root. Yank and destroy any infested root instead of tossing it on the compost. Then throw a floating row cover over the bed at sowing and march your brassicas to fresh ground each year to shut the flies out.
Fix:
- Remove and destroy infested roots
- Avoid planting brassicas in the same bed in successive years
Stunted plants with swollen, club-shaped roots
Swollen, twisted roots and midday wilting call out clubroot, a soil-borne disease that digs in for years once it lands. Nothing cures it, so pull the infected plants and bin them rather than composting. Push the soil pH near 7.0, sharpen the drainage, and rotate well clear of cabbage-family crops to keep it from spreading.
Fix:
- Remove and destroy infected plants
- Do not compost infected material
Small round shot-holes across the young leaves
Those little round holes riddling the leaves are flea beetle work, and the beetles pounce hardest on small seedlings in warm, dry spells. Give the foliage a tap and watch the tiny black beetles ping away. Cover the seedlings the moment they break ground and keep them watered so they outrun the chewing and power on through.
Fix:
- Cover seedlings with row cover
- Keep plants well watered and vigorous to outgrow damage
Brown, watery core inside a root that looks fine
A root that looks great outside but hides a grey-brown, corky, bitter center has brown heart, and it traces back to a boron shortage in the soil. Slice one open and the core has broken down while the skin still looks sound. Run a soil test before adding any boron, since too much turns toxic, and keep the water coming, especially on lighter ground.
Fix:
- Apply boron-containing fertilizer only per a soil test
- Maintain even soil moisture
Toxicity
Here is the easy part: rutabaga is food through and through, and every part is safe for people and animals alike. Cooks and stockkeepers have eaten and fed these roots and tops for ages, so nothing here needs worrying over beyond keeping things sensible.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cooked or raw, rutabaga is perfectly safe for a cat, even if most cats shrug it off. A quick nibble of root or leaf does no harm at all.
Dogs None
Plain rutabaga makes a great little treat for a dog, and plenty pounce on a cooked piece. Keep the helping small, though, so the extra fiber does not upset a touchy stomach.
Horses Safe
Horses tuck into rutabaga with no trouble. Chop it into small chunks rather than handing over a whole root, which is far too easy to choke on.
Rabbits Safe
Both the root and the leafy tops are safe for rabbits as part of a mixed diet. Roll any new vegetable in slowly so the gut has time to catch up.
Livestock Safe
Rutabaga has powered cattle and sheep through winter for ages, roots and tops alike. Grazing hard on the raw brassica day after day can press on thyroid function through its natural goitrogens, so balance it out with other forage.
Birds Safe
Chickens and other backyard birds dive right in at the root and greens with no ill effect. Chop it small so they can make quick work of it.
People Safe
For the cook, rutabaga is a great kitchen vegetable, brilliant roasted, mashed, or dropped into a stew. Both the roots and the young leaves are 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 the catalogs, and they run pretty close to one another. Even so, these are the names any keen grower keeps handy.
American Purple Top
The go-to standard for most growers, throwing globe-shaped roots with purple shoulders over yellow flesh that flushes orange once it hits the pan.
Laurentian
A uniform purple-top loved for fine-grained, sweet yellow flesh, a top pick to pack away for fall storage.
Joan
An early, smooth-skinned purple-top that comes loaded with handy tolerance to clubroot.
How to propagate
Rutabaga grows from seed, full stop, dropped right where it will live out its season. It hates being uprooted, so skip the transplanting fuss and let it settle in from day one.
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
Drop rutabaga seed right where it will grow, tucking it about a quarter to half an inch deep any time from late spring to mid-summer for a fall crop. The seedlings shoot up within a week or two, and you thin them to roughly 8 inches apart so each root can bulk up to full size over the next 90 to 100 days. Skip the transplanting altogether, since rutabaga resents being moved and always races ahead when sown right where it will grow.
Myths
Rutabaga and turnip are just the same vegetable.
Not so, they are two separate species that grow their own way. Rutabaga is the bigger, yellow-fleshed, sweeter root built for a long cool season, while turnip races ahead as a smaller, white-fleshed crop you pull within weeks.
Pull rutabagas before frost or they will spoil.
Frost is the best thing going for this crop. One or two hard freezes flip the root's starch to sugar, so the flavor jumps after frost, and the standout harvest waits until those cold nights have worked their magic.