How to grow rutabaga
Family Brassicaceae. Hardy to USDA hardiness zone 3a+ (U.S. Department of Agriculture). Full sun. Ready in 80-100 days.
Sun
Full sun
Spacing
6-8 in
Days to harvest
80-100 days
Hardiness
Zone 3a+
What growers actually recorded
Loading zone 7b results…
When to plant rutabaga
- Direct sow: ~-12 weeks after last frost.
Companion plants for rutabaga
Plant with: Pea, Onion, Thyme.
Avoid near: Other brassicas in rotation.
Common pests & problems
Root maggot, flea beetle, cabbage worm.
Feeding & fertilizer
N-P-K ratio: High N (10-5-5): heavy feeders
Organic options: Aged manure or compost worked in deep · Blood meal or feather meal side-dress at 3 wks · Fish emulsion every 2 wks
When to feed: Feed heavily every 2-3 weeks. Brassicas want steady nitrogen for tight heads.
Watch for: Pale/yellow leaves = needs N. Loose heads = feed harder next round.
N = nitrogen (leaves), P = phosphorus (roots and flowers), K = potassium (fruit and disease resistance). How to read a fertilizer label →
Grower's tip
Sow in mid-summer for a fall harvest; a light frost sweetens the root before you pull it.
When to plant rutabaga in your zone
Free month-by-month sowing and transplanting lists, built from frost dates for your USDA (United States Department of Agriculture) hardiness zone.
Soil & water for rutabaga
Soil & pH
6.5-7.5: near neutral (raises club-root resistance)
Fertile loam with strong drainage. Firm soil beats fluffy for heading brassicas.
Compost 2 in + 1 cup of alfalfa or feather meal per 10 sq ft. Lime if pH is under 6.5. It also blocks club-root.
Watering
1-1.5 in / week, consistent
Ground-level drip. Uneven water during heading = split heads or bolting.
Lift an edge of the row and check soil at 3 inches. If it clings in a damp ball, hold off. If it crumbles, water until the top 6 inches are evenly moist.
Knowing when to harvest
- Root reaches 3-5 in across, purple-topped and firm.
- Harvest after a light frost, which sweetens the root the same way it does turnip and parsnip.
- Skin should feel smooth and give slight resistance to a thumbnail, not soft or spongy.
Storing & keeping
Wax or store unwashed in damp sand at 32-40°F, 90-95% humidity for 4-6 months, the longest-keeping of the common root brassicas.
What to expect
Per plant: 1 root, 1-3 lb
Per sq ft: 4-6 roots per sq ft
Troubleshooting rutabaga
Small or forked roots
Likely cause: Crowded spacing or rocky, compacted soil
What to do: Thin to 8-10 in apart and grow in loosened, stone-free soil.
Woody texture
Likely cause: Harvested too late or grown through heat
What to do: Sow in mid-summer for a fall harvest; rutabaga needs a longer, cooler season than turnip and dislikes heat during root swell.
Varieties worth growing
American Purple Top
The standard variety, reliable size and storage quality.
Laurentian
Smooth-skinned, popular commercial type with good keeping ability.
Growing rutabaga in containers
Poor container crop: rutabaga needs a long season (90+ days) and deep, fertile soil that most pots can't sustain without frequent feeding and watering.
Nutrition
Sulforaphane, glucosinolates, vitamin K, calcium. Brassicas are the vegetable powerhouse.
Common questions
What's the difference between rutabaga and turnip?
Rutabaga is a cross between turnip and cabbage, with a longer growing season, denser flesh, and better long-term storage life than turnip.
Should I wax rutabagas before storing?
Commercial growers wax them to prevent moisture loss; home growers can get similar results storing roots in damp sand in a cool cellar.
Where these numbers come from
- USDA Plant Hardiness Zone Map (2023 revision). Zone assignment and the 30-year normals behind every cold-hardiness figure.
- NOAA NCEI 1991-2020 Climate Normals. Frost dates, growing-season length, and the probability bands on both.
- Cornell, UMN, and UC Davis Cooperative Extension crop guides. Spacing, days to maturity, soil pH targets, and per-plant yield ranges.
- USDA FSIS / FDA Produce Safety guidance. Wash, cure, and cold-storage handling numbers.
Ranges are regional guidance, not a promise for your yard. Your own logged results always override the published range.