Vegetable · Brassicaceae
Rutabaga
Brassica napus subsp. rapifera
Pop the seed in during summer, wait out the season, and once a hard frost sweetens the roots you've got a fall crop that keeps for ages.
Full sun
Every 3–7 days
41–77°F · 5–25°C
90–100 days
Overview
So what exactly is a rutabaga? It's a cool-season root in the cabbage family, grown for that hefty, yellow-fleshed root that pushes up to the soil line. It probably started out as a turnip crossed with a wild cabbage, and it's been feeding northern families and their livestock through winter for hundreds of years. You'll also see it labeled the swede or Swedish turnip, and it's happiest where summers stay easygoing and fall gets properly cold.
The one thing rutabaga really wants is time. It needs a long, cool season of around 90 to 100 days, which is a lot more than a quick little turnip, and it hits its stride as the weather starts cooling off. Toss the roots in a cool cellar and they'll keep for months, which is exactly why folks leaned on them long before anybody had a fridge.
Here's the easy part: once it's in the ground, it doesn't ask for much. Give it deep, loose soil, water that doesn't dry out, and a bit of room to spread, and the weather takes care of the rest. A couple of hard freezes and the starch turns to sugar, so the root you dig in late fall tastes way sweeter than one you rush out of the ground too soon.
Care
The short version: rutabaga wants full sun and deep, loose, well-drained soil, plus about an inch of water a week so the roots don't go woody. Sow it in summer, thin the seedlings to 8 inches apart, and don't harvest until fall after a hard frost or two.
Light
Rutabaga does best in full sun, so think about 6 or more hours of direct light a day. A little partial shade won't kill it, but where the light's thin the roots take their sweet time and stay on the small side.
Water
Keep things evenly moist, roughly an inch of water a week, and watch it especially while the roots are filling out. Let the soil bounce between bone dry and soaked, though, and you'll end up with woody, cracked, bitter roots instead of sweet ones.
Soil
Rutabaga likes deep, loose, fertile loam that drains well and has plenty of organic matter, with the stones pulled out so the root can dive straight down. Shoot for a pH of 6.0 to 7.0, and staying near the top of that range helps keep clubroot from moving in.
Temperature
This is a cool-weather crop through and through, happy between 41°F and 77°F (5°C to 25°C), and it only gets sweeter as things cool off. Heat just makes the roots tough and sharp, while fall's frosts are what flip the starch over to sugar.
Humidity
No need to worry about humidity, since regular outdoor air is plenty. What actually matters is steady soil moisture and decent airflow around the leaves so leaf diseases don't get comfortable.
Feeding
About 3 to 4 weeks after planting, give it a side-dressing of nitrogen, like calcium nitrate or a balanced fertilizer, to get the leaves going before the roots bulk up. If you dug compost in ahead of time, that already does a lot of the work.
Pruning
There's nothing to prune here, really. Just thin the seedlings to about 8 inches apart so each root has room to get big and round, and pull off any diseased leaves you notice while you're at it.
Size & spacing
Up top, the plants get to about 12 to 18 inches (30 to 45 cm) tall, while the swollen root sits right at the soil line. Give each one roughly 8 inches (20 cm) of space and the roots have all the room they need to fill out.
When to plant
Rutabaga is one of those crops you start in the summer heat and finish in the cold, funny as that sounds. Go ahead and direct sow from late spring through mid-summer, give it the long cool run it needs to size up, and hold off digging until a hard frost or two has sweetened the roots.
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 headaches happen where you can't see them, down at the root or on the baby seedlings. The trick is spotting the clues up top so you can jump in before a soil pest or disease wrecks things. Find whatever matches what you're seeing below, then deal with it while it still helps.
Brown tunnels boring through the root with wilting outer leaves
See tunnels running through the flesh and the outer leaves flopping over? That's the cabbage maggot, whose larvae chew their way through the root near the crown. Dig up anything that's infested and get rid of it, don't compost it. From then on, throw a floating row cover over the bed at sowing and move your brassicas to fresh ground each year so the flies can't settle in.
Fix:
- Remove and destroy infested roots
- Avoid planting brassicas in the same bed in successive years
Stunted plants with swollen, club-shaped roots
Swollen, weirdly distorted roots plus wilting in the midday heat usually mean clubroot, a soil disease that hangs around for years once it shows up. There's no fixing it, so pull the infected plants and bin them rather than composting. Keep your soil pH near 7.0, sort out the drainage, and rotate well away from cabbage-family crops.
Fix:
- Remove and destroy infected plants
- Do not compost infected material
Small round shot-holes across the young leaves
Those little round holes all over the leaves? That's flea beetle work, and they go hardest on small seedlings in warm, dry weather. Give the foliage a tap and you'll watch the tiny black beetles hop away. Cover the seedlings the day they come up and keep them watered so they grow faster than the beetles can nibble.
Fix:
- Cover seedlings with row cover
- Keep plants well watered and vigorous to outgrow damage
Brown, watery core inside a root that looks fine
If a root looks normal outside but the middle's gone grey-brown and bitter, that's brown heart, and it comes down to not enough boron in the soil. Cut one open and you'll see the core's broken down while the skin's still fine. Get a soil test before adding any boron, since too much is toxic, and keep the watering steady, especially on lighter ground.
Fix:
- Apply boron-containing fertilizer only per a soil test
- Maintain even soil moisture
Toxicity
Good news here: rutabaga is food, and every bit of it is safe for people and animals alike. The roots and the leafy tops have been eaten and fed to livestock forever, so there's really nothing to stress about beyond not going overboard.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cooked or raw, rutabaga is totally safe for a cat, though most cats couldn't care less about it. A little nibble of root or a leaf won't do any harm.
Dogs None
Plain rutabaga makes a nice little treat for a dog, and plenty of them are happy to crunch a cooked piece. Just keep the portions small so the extra fiber doesn't upset a touchy stomach.
Horses Safe
Horses can eat rutabaga no problem. Slice it into small chunks instead of handing over a whole root, though, since a big one's easy to choke on.
Rabbits Safe
Both the root and the leafy tops are fine for rabbits as part of a mixed diet. Introduce anything new slowly, so their gut has time to catch up.
Livestock Safe
Rutabaga's been winter feed for cattle and sheep for ages, roots and tops and all. Grazing hard on the raw brassica day after day can lean on thyroid function thanks to its natural goitrogens, so mix it up with other forage.
Birds Safe
Chickens and other backyard birds are more than happy to peck at the root and the greens, no harm done. Chop it up small so it's easy for them to deal with.
People Safe
For people, rutabaga is a great kitchen vegetable, whether it's roasted, mashed, or thrown in 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
You won't find a huge lineup of rutabaga varieties in the catalogs, and honestly they're pretty similar. Still, these are the few names worth knowing.
American Purple Top
It's the standard everybody grows, with round roots that show purple shoulders over yellow flesh that goes orange once you cook it.
Laurentian
This one's an even, uniform purple-top with fine-grained, sweet yellow flesh, which is why it's such a go-to for fall storage.
Joan
An early, smooth-skinned purple-top that's got a handy bit of tolerance to clubroot built right in.
How to propagate
Rutabaga grows from seed, and that's it, sown right where it's going to live. It hates being moved, so why bother with transplanting? There's no shortcut worth the trouble.
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
Just sow rutabaga right where it'll grow, dropping the seed about a quarter to half an inch deep any time from late spring to mid-summer for a fall crop. The seedlings usually pop up within a week or two, and you thin them to about 8 inches apart so each root has room to swell to full size over the next 90 to 100 days. Don't bother transplanting, since rutabaga hates being moved and always does better sown right where it'll stay.
Myths
Rutabaga and turnip are really just the same vegetable.
Nope, they're actually two different species that grow their own way. Rutabaga is the bigger, yellow-fleshed, sweeter root that needs a long cool season, while a turnip is quicker and smaller with white flesh you can pull in a matter of weeks.
You have to harvest rutabagas before frost or they'll spoil.
Actually, frost is the best thing for them. A hard freeze or two turns the root's starch into sugar, so they taste better after frost, and the finest harvest waits until those cold nights have done their thing.