Growing swede: sowing, bulking and winter harvest

Swede or turnip: which to choose?

Swede, also known as rutabaga, is Brassica napus group Napobrassica; British sources use the name swede. The turnip belongs to Brassica rapa. Their names sometimes overlap, but their growth rates differ: do not apply the schedule of a small turnip to a swede. Minnesota · RHS

The SNHF lists ‘Jaune à collet rouge’, ‘Jaune à collet vert’ and ‘Blanc hors terre’. For cooking, check the intended use and flesh type indicated on the seed packet. For an extended harvest, also compare their ability to remain tender and store well. SNHF · RHS

When to sow and which soil to prepare?

The SNHF provides a French guideline from spring to early summer. Adjust this based on the variety, soil drainage, and available growing time before winter. Sowing in soil that is still unworkable is not justified by the calendar alone. SNHF

Choose a sunny spot with humus-rich, well-drained, non-compacted soil. A raised bed can help if the ground becomes waterlogged. Enhance fertility with mature garden compost; avoid fresh manure, which may encourage branched roots. Adjust other inputs based on soil fertility, without systematically adding nitrogen. Iowa · Minnesota

Sowing, thinning or planting a plug

Sow directly in place where possible, in prepared and moistened rows. The SNHF recommends covering seeds with 1 to 2 cm of soil, spacing rows 40 cm apart, then thinning to 25 cm between plants. Keep the surface moist during establishment. The sowing guide helps prepare and mark rows. SNHF

Starting in modules is possible: the RHS advises transplanting young plugs before the main taproot develops, disturbing roots minimally and after acclimatisation. Containers are best suited for small roots harvested young, not for large storage swedes. RHS

Supporting bulking without damaging the root

Water when the soil dries out and ensure moisture reaches the root zone. Drought can result in hard or bitter roots; a large swelling is not a sufficient water reserve for the entire season. Minnesota

Hoe shallowly, as roots develop near the surface. After thinning, a light mulch helps retain moisture and reduce competition. If growth slows, first check spacing, moisture under the mulch, and soil structure before considering additional inputs. Iowa

Leaves with holes or weak growth: what to observe?

On seedlings, look for small round holes and beetles that jump when approached: this suggests flea beetles. Insect-proof netting can be a preventive measure; a few holes on a large plant have less impact than on a young seedling. RHS flea beetles

If persistent wilting occurs, also inspect the roots of an affected plant. Significant deformations and loss of fine roots may indicate clubroot, though foliage alone does not confirm it. Avoid transferring suspect soil on tools or with plants. Have uncertain cases confirmed before making multiple soil amendments. RHS clubroot

Include swede with brassicas in your crop rotation: following it with cabbage or turnip does not change the family. This prevention does not guarantee the remediation of soil affected by clubroot. Minnesota · RHS clubroot

Harvesting at the right stage and responding to bolting

The SNHF suggests an initial harvest three to four months after sowing; the RHS also describes crops lasting up to six months. These are variable guidelines. Test a root for tenderness; the typical harvest size may reach 10 to 13 cm, though waiting for this size is not mandatory. SNHF · RHS · Iowa

An elongating stem and flowering signal a shift in purpose: bolting in root vegetables can stop the roots bulking up. Do not wait for flowers to decide on harvesting, nor rely on cutting them to restore root quality. RHS bolting

Leave in the ground or store for winter?

Lift roots with a fork placed alongside, then remove foliage and avoid damage. Very cold or persistently wet soil makes early lifting preferable before winter difficulties; elsewhere, protective covering allows extended harvesting. Minnesota · RHS

For storage after lifting, the RHS suggests crates of moist sand in a cool, frost-free location. Monitor roots: drying causes shrivelling, while damaged or rotting roots should be discarded. Storage durations of several months described by universities rely on controlled temperature and humidity; they are not a guarantee for every cellar. RHS · Minnesota · Iowa