Lactuca sativa.
A historic figure of North American market gardening. Developed around 1890 by Eugene Davis, a market gardener of Grand Rapids, Michigan, it was specifically selected for forcing under glass — it's the one that, at the turn of the 20th century, made possible the commercial production of winter lettuce in the cold regions of the American Northeast and Midwest, and that long dominated grocery stores from January to March before the arrival of fast transport from California. An old variety, but astonishingly modern for its time.
Brilliant lime-green leaves, very frilly and wavy at the edges, with a texture both tender and crunchy, mild, fresh in flavour, without bitterness. A loose-leaf type for progressive picking — take outer leaves as needed, and the plant keeps producing from the centre. A precious peculiarity: it's one of the most cold-hardy lettuces — it germinates at temperatures where the others remain dormant, sails through light frosts unfazed, and gives beautiful harvests very early in spring and very late in fall, as well as under unheated tunnel. For winter gardeners equipped with a cold greenhouse or cold frame, it remains a reference today.
Grower's tip: Grand Rapids needs light to germinate — it's hard-coded genetically. Sow on the surface or cover with barely 2-3 mm of fine potting mix, no more, or emergence will fail. Unlike most lettuces, its germination tolerates relatively low temperatures (10 to 15 °C), which lets you sow it earlier than any other — from late March under tunnel or in a cold greenhouse in Québec. To stretch the harvest, sow in successive rows every 10-14 days.
- Open-pollinated. Heirloom variety. Self-fertile, so very few crossings to fear — ideal for seed saving.
- Height: 20 to 25 cm.
- Maturity: 45 to 50 days for the full rosette; young leaves from 25 days.
- Exposure: full sun in spring and fall, part shade in midsummer.
- Rich, fresh, well-drained soil. Thin to 20 cm for full rosettes, or sow densely for young-leaf picking.
- Direct-sow as soon as the soil can be worked — one of the first lettuces you can sow (late March / early April under tunnel, mid-April in the open field in Québec). Excellent also for late-summer sowings and cold-greenhouse culture for winter harvest.
