Raphanus sativus.
An ancient heirloom variety, listed in European and North American catalogues since 1828, and probably cultivated long before that in Spanish and Eastern European gardens. The name is misleading — despite the "Spanish" qualifier, the black radish's origin is probably Asian, but it was through medieval Spain that it spread into Europe in the 16th century. It enjoyed a particular fortune in the Ashkenazi Jewish cooking of Eastern Europe, where under the Yiddish name schwartz reddich it became one of the ritual foods of the Sabbath, grated in chiffonade with chicken fat (schmaltz), salt and plenty of pepper, served on black bread or matzo. In Russian and Polish traditions, you cut it in thin rounds and cover them with honey to fight coughs and sore throats — a folk remedy of an effectiveness astonishingly supported by some modern studies on its sulphur compounds.
Globe-shaped root 7 to 10 cm across, with matte, almost charcoal-black skin — a striking visual contrast when you cut it in two to reveal pure white flesh, firm, crunchy, dense, much hotter and spicier than that of spring radishes. At table, grated raw as a condiment that wakes you up, in fine julienne in a fall salad (rivalling turnip in pungency), thinly sliced on a French-style half-salted butter sandwich, or baked in a gratin to soften its bite (a little like turnip).
For storage, it's a champion: in the root cellar under lightly damp sand, or simply in a cold room, it holds 4 to 6 months without flinching — a real winter resource, to include in any garden plan meant to feed a family beyond frost.
Grower's tip: Like daikon and China Rose, it's a fall radish par excellence. Sown in spring, it bolts under summer heat before properly forming its root. The ideal window in Québec: early to mid-August for a harvest from late September to mid-October. Deeply loosened soil (20 to 25 cm), free of stones and fresh manure that would deform the root. Harvest before hard frosts (a light frost doesn't hurt — it even slightly improves the flesh); save the cut tops to add sautéed to a potato soup.
- Open-pollinated. Annual to biennial depending on conditions. Insect-pollinated; crosses with other radishes nearby — isolate for seed saving.
- Top height: 25 to 35 cm.
- Maturity: 55 to 60 days.
- Exposure: full sun.
- Loose, deep (20-25 cm) soil, free of stones and fresh manure. Thin to 10-15 cm.
- Direct-sow early to mid-August in Québec for the fall harvest. Tolerates light frosts well, which improve the flesh. Excellent winter-keeper vegetable.
