Brassica rapa.

Commonly called rabioles in Québec — an essential heirloom variety, grown in North America since at least the 1880s and in European gardens long before. Its silhouette is unmistakable: a perfectly round globe, pearly white below ground, capped with a brilliant purple where it has seen the sun. A visual signature in the harvest basket, and a sweet, mild flesh, almost crunchy when eaten young and raw — grated into a salad with a little salt, it's a revelation.

The turnip is the discreet companion of traditional Québec cooking — pot-au-feu, ragoût de pattes, an October soup when the wind starts to bite. A non-negligible bonus: the tops are delicious, more nutritious than spinach, and cook like cabbage or Swiss chard — two harvests in one.

Grower's tip: The turnip hates being transplanted — its taproots hold a grudge. Always sow in place, and resist the temptation to over-fertilize: soil too rich in nitrogen will give you magnificent tops and tiny roots. Better a loose, modest soil well worked in depth. And patience for the fall harvest — the first frosts concentrate the sugars and transform the flavour.

• Open-pollinated.
• Maturity: 50 to 55 days.
• Root size: 8 to 12 cm across.
• Exposure: full sun.
• Loose, well-drained, slightly acid to neutral soil. Not too much nitrogen. Thin to 10 cm.
• Direct-sow, in two possible waves: early spring as soon as the soil can be worked (June harvest), then late July to early August for a fall harvest (the best — improved by light frosts).