Direct-Sowing Spinach & Lettuce in Alberta

When to plant

As soon as the soil can be worked. Spinach germinates at 4°C, lettuce at 7°C — both well below what tomatoes or peppers tolerate. Mid-April in southern and central Alberta is typical; early May in the north. A second sowing in late July through mid-August catches the cool fall window and gives you October harvests.

Skip late-June plantings unless you have shade. Hot soil produces poor germination and bolt-prone seedlings.

Soil prep

Both crops want loose, fertile soil with consistent moisture. Work in 5 cm of compost before planting. Lettuce in particular has a shallow root system and depends on what’s in the top 15 cm of soil.

How to plant

• Make shallow furrows 1–1.5 cm deep.
• Sow seeds thinly — aim for one seed every 2–3 cm. They’re tiny so this is easier said than done.
• Cover lightly, water with a fine spray, and keep the soil consistently moist until germination (5–14 days for both).
• Thin lettuce to 10 cm apart for cut-and-come-again leaves, or 20–30 cm for full heads. Thin spinach to 8–10 cm.
• Eat the thinnings — baby spinach and lettuce thinnings are the most expensive thing at the grocery store and the most rewarding part of growing.

Succession sowing

Sow a 1 m row every 2–3 weeks from mid-April through late May. Each row provides 4–5 weeks of harvest before bolting. By the time the first row is bolting, the third or fourth row is hitting cut-and-come-again size.

Pause sowing in late June and July when heat makes germination unreliable. Resume in August for fall crops — sow August 1, August 15, and September 1 for harvests through October and into November under row cover.

Bolt-resistant variety picks

• Spinach — Bloomsdale Long Standing: Heritage, slow-bolting, cold-hardy. The reliable Alberta choice.
• Spinach — Tyee: Modern, very slow to bolt, productive into early summer.
• Lettuce — Buttercrunch: Bibb-type, heat-tolerant, holds well in the heat without turning bitter.
• Lettuce — Red Sails: Loose-leaf, slow-bolting, beautiful red colour.
• Lettuce — Salad Bowl: Loose-leaf, long-standing, the classic cut-and-come-again pick.

Harvesting

For both crops, harvest outer leaves first and let the centre keep growing — you’ll get 3–5 cuts per plant before bolting. For full lettuce heads, cut at the base when the head feels firm. Spinach for cooking can be cut whole at the base when leaves are 10–15 cm long.

Harvest in the morning when leaves are full of water and crisp. Lettuce harvested in the afternoon heat goes limp fast and won’t recover.