The rutabaga (Brassica napus var. napobrassica) is a hardy root vegetable resulting from a natural cross between a turnip and a cabbage. This cool-weather crop is prized for its sweet, earthy flavor, which develops best when the roots mature in colder temperatures. Successfully cultivating rutabagas requires careful attention to timing, soil preparation, and specific maintenance routines throughout the growing season.
Preparing the Growing Environment (Soil and Timing)
Rutabagas are a cool-season vegetable demanding 90 to 120 days from seed to maturity. Planting usually occurs in mid-to-late summer in most temperate climates. This timing ensures the roots develop during late summer but mature in the cooler temperatures of fall and early winter, which naturally sweetens the root.
The ideal planting site receives full sun (at least six hours of direct sunlight daily). Rutabagas require a deep, loose, and well-draining medium to expand properly. Compacted or heavy clay soils restrict growth and lead to poorly formed, forked, or small roots.
Aim for a soil pH that is slightly acidic to neutral, ideally ranging between 6.0 and 7.0. Before planting, incorporate substantial amounts of well-rotted organic matter, such as finished compost, deeply into the soil. This improves structure, increases water retention, and provides sustained fertility. Avoid using fresh animal manure, as its high nitrogen content encourages excessive leaf growth and can promote undesirable hairy roots.
Sowing Seeds and Managing Early Growth
While rutabagas can be transplanted, direct sowing the seeds is the preferred method to avoid disturbing the sensitive taproot. Plant the seeds shallowly, covering them with about one-half inch of fine soil, and keep the seedbed consistently moist until germination. Initial spacing should be close, aiming for one to two inches between seeds, to ensure good germination rates.
The most important step is the timely and aggressive thinning of the seedlings. Overcrowding is the primary cause of small, underdeveloped roots, as competing plants struggle for resources. Thinning must occur promptly when the seedlings develop their second set of true leaves.
Carefully remove the weaker seedlings by snipping them at the soil line with scissors to avoid disturbing the roots of remaining plants. Leave only the strongest plants spaced six to eight inches apart in all directions. This final spacing allows the storage root to swell to its full size of three to five inches in diameter before the first hard frost.
A light application of a balanced, low-nitrogen fertilizer can be beneficial when the seedlings are first thinned. This initial feeding supports the rapid formation of large, photosynthesizing leaves necessary for energy production. Focus on providing adequate phosphorus and potassium to aid in strong, deep root establishment.
Mid-Season Watering and Pest Management
Consistent soil moisture is essential once the rutabaga plants have passed the seedling stage, as uneven watering compromises the quality of the harvest. Deep, regular watering is necessary, especially during dry weather or high heat, to maintain uniform moisture levels. Allowing the soil to dry out and then flooding it can cause developing roots to split or crack, rendering them woody and inedible.
As members of the Brassica family, rutabagas are susceptible to several common pests. Flea beetles chew small perforations in young leaves, and cabbage worms skeletonize the foliage. Employing lightweight floating row covers immediately after planting is an effective physical barrier against these flying insects.
Root maggots are also a threat, as their larvae bore into the developing root, causing decay and stunted growth. Implementing a strict crop rotation schedule helps reduce root maggot populations, as they overwinter near previous host plants. Applying diatomaceous earth around the base of the stems can deter crawling pests.
As the storage roots swell and push up through the soil surface, gently hilling soil up around the exposed shoulders is important. This prevents the tops of the roots from turning green and bitter, a condition known as “sunburn” caused by direct sunlight. Consistent hilling also provides additional support to the large foliage.
Harvesting and Post-Harvest Handling
Rutabagas are typically ready for harvest once the swollen roots reach three to five inches in diameter. The flavor improves significantly after the plants experience one or two light frosts, as this cold exposure triggers the enzymatic conversion of starches into sweeter, more palatable sugars.
To harvest, gently loosen the soil around the plant using a garden fork or trowel, taking care not to puncture the root. Once lifted, remove the bulk of the attached greens immediately, leaving only about an inch of the stem attached. This small section of stem helps prevent excessive moisture loss during storage and minimizes the risk of decay organisms entering the root.
For long-term storage, rutabagas require curing. Brush off any excess soil but avoid washing the roots before storage, as moisture encourages mold growth. The ideal storage environment is a cool, dark, and humid location, such as a root cellar, maintained at temperatures near 32 to 40 degrees Fahrenheit. Rutabagas can be stored successfully for four to six months, providing fresh vegetables well into the winter and spring.