Now
16°C · Clear
Today
20° / 12°
Soil 6 cm
17°C
First frost
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Gardening in Quebec
AI field guide · refreshed weeklyQuebec Gardening: Early September – Harvest Season Begins, Winter Prep Underway
Zone 5a means your average first frost arrives October 16—just 38 days away. Soil at 17°C is still warm enough for germination but cooling fast; anything you sow now must mature before mid-October. Spring frost averaged May 12, giving you a 157-day growing season. Frost-free days are nearly behind you; focus on harvesting and protecting what's in the ground.
Sow outdoors now
Spinach (Spinacia oleracea)
Direct sow 'Space' or 'Bloomsdale' now for a quick fall crop; germinates in 7–10 days at 17°C soil and matures in 40–50 days before frost.
Arugula (Eruca vesicana)
Sow 'Roquette' or 'Wild' for peppery leaves in 30–40 days; thrives in cooling weather and tolerates light frosts.
Radish (Raphanus sativus)
Plant 'Cherry Belle' or 'French Breakfast' for harvest in 25–30 days; cold actually improves flavor and crispness.
Mâche (Valerianella locusta)
Sow 'Verte de Cambrai' now for a hardy winter green; survives frosts and provides fresh leaves through November.
Turnip (Brassica rapa subsp. rapa)
Direct sow 'Purple Top' or 'Hakurei' for roots and greens; matures in 50–60 days and stores well after frost.
Start indoors now
Garlic (Allium sativum)
Separate cloves from hardneck varieties like 'German Extra Hardy' or 'Chesnok Red' and chill at 4°C for 4–6 weeks before planting outdoors in late September; this cold period triggers dormancy and spring sprouting.
Onion seeds (Allium cepa)
Start 'Copra' or 'Walla Walla' indoors under lights now to transplant outdoors in 4–6 weeks for overwintering; they'll establish roots before soil freezes.
Harvest now
Tomato (Solanum lycopersicum)
Pick all remaining fruit—both ripe and mature green—before the first frost; mature greens ripen indoors in 1–2 weeks at room temperature.
Pepper (Capsicum annuum)
Harvest all peppers, even immature ones; they won't ripen further outdoors as nights cool below 15°C.
Cucumber (Cucumis sativus) & Squash (Cucurbita spp.)
Pick all remaining fruit and cut vines; frost will kill them within weeks, so don't wait for perfection.
Carrot (Daucus carota subsp. sativus) & Beet (Beta vulgaris)
Begin harvesting; cold soil actually sweetens roots, and they store for months in a cool cellar or root box.
Tasks this week
- Pull spent summer annuals (beans, basil, zucchini) to reduce disease and clear space for fall crops.
- Mulch garlic and onion beds with 5–8 cm (2–3 in) of aged compost or straw after planting to insulate roots through winter.
- Cut back perennial herbs (mint, oregano, thyme) by one-third to encourage bushy growth before dormancy.
- Sow cover crops (winter rye, hairy vetch) in empty beds to prevent erosion and add nitrogen by spring.
- Drain and store garden hoses and irrigation lines before frost; flush lines with air to prevent ice damage.
Watch out for
- Powdery mildew thrives in cool, humid fall air—thin foliage on squash and cucumbers to improve airflow, and remove infected leaves promptly.
- Early blight on tomatoes accelerates as nights cool; remove lower leaves and harvest all fruit before the first frost (Oct 16).
- Slugs and snails are most active in moist fall weather—hand-pick in early morning or use beer traps in damp mulch.
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