Rutabaga

Quick facts

Category

roots bulbs

Difficulty

beginner

Days to harvest

90 to 120 days

Harvest type

single harvest then replant

Spacing

25 cm between plants

Environment

Temperature

4–22°C

pH

6 to 7

EC (hydroponic)

1.4 to 2 mS/cm

Daily light

14 to 22 mol/m²/day

Climate and zones

USDA zones

2 to 8 (winter low around -46°C or warmer)

Frost tolerance

very hardy (survives deep cold)

Season

cool (spring and fall crops)

Viable growing environments:

• outdoor year-round (in zone)
• outdoor in growing season (annual)
• unheated greenhouse / hoop house

USDA zone bounds reflect outdoor year-round survival. Anywhere outside the bounded zone range, this crop still grows as an annual in the warm months (outdoor_seasonal), under cover (greenhouse), or indoors under lights.

Growing systems

Rutabaga works in:

• media bed (ebb and flow)
• wicking bed
• soil bed

Root mass is heavy - thin-channel systems (NFT, vertical towers) can't hold this crop mechanically, hence the system list above.

Growing media

The substrate the roots sit in. Choice depends on the system (clay pebbles don't fit NFT channels; rockwool isn't used in media beds) and the crop (rutabaga works in the media listed below).

Bacterial surface area matters for aquaponics: clay pebbles, lava rock, and pumice double as biofilter substrate. Low-surface media (rockwool, perlite, pea gravel) work in hydroponics but need a separate biofilter in aquaponics.

Nutrient demand by stage

NPK ratios are relative weights at each growth stage; the nutrient mix calculator scales them to absolute grams or ml. EC targets shift through the plant's life: seedlings need a much lighter solution than fruiting adults.

Aquaponics suitability

Compatible with typical aquaponics nutrient profiles. Fish waste provides enough nitrogen for healthy growth; supplemental potassium, calcium, and iron may still be needed depending on fish stocking density.

Care notes

A cool-season root crop for media beds or large containers (15 cm depth). EC 1.5-2.5 mS/cm. pH 6.0-7.0. Temperature: 10–22°C (cool-season; above 25°C, roots become woody and bitter). Moderate light (DLI 14-20 mol/m2/day). From seed to harvest: 80-100 days (longer than turnips, which are 40-60 days). Direct seed or transplant into deep, loose media. Thin to 15–20 cm spacing (rutabaga roots grow large, 8–15 cm diameter). Harvest after the first frost if possible; frost-sweetened rutabaga is noticeably better than warm-weather-grown. For mashed rutabaga: peel, cube, boil until tender, mash with butter, salt, and white pepper. The flavor is sweeter and more complex than mashed potatoes. Boron deficiency causes brown, corky internal discoloration (brown heart); ensure the nutrient solution includes adequate boron. Cabbage root maggot is the main pest. Rutabaga stores for 3-6 months at 1–4°C with high humidity.

Notable varieties

A starting shortlist of cultivars worth knowing about. Not exhaustive: the seed catalogs list hundreds of named varieties. These are the ones home growers commonly choose between.

Further reading

• Best crops for hydroponic beginners
• The Kratky method: grow lettuce with zero electricity