Now
10°C · Drizzle
Today
12° / 9°
Soil 6 cm
11°C
First frost
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Gardening in Thompson
AI field guide · refreshed weeklyThompson, MB Gardening: Early September – Race Against Frost
Zone 3b means you have roughly 23 days until the average first frost (Oct 1). Soil at 11°C is cool but workable for fall crops; frost-sensitive plants are done. Spring frost averaged May 26, giving you 128 frost-free days annually. Plan all sowings and plantings with Oct 1 as your hard deadline.
Sow outdoors now
Spinach (Spinacia oleracea 'Space' or 'Bloomsdale')
Direct-sow now for a quick fall crop; germinates well in cool soil and tolerates light frosts. Harvest in 40–50 days, well before hard freeze.
Arugula (Eruca sativa)
Fast-growing (30 days), cold-tolerant, and thrives in 11°C soil. Sow thickly in rows or broadcast; thin to 10 cm spacing.
Radish (Raphanus sativus 'Cherry Belle' or 'Icicle')
Matures in 25–30 days in cool weather. Sow now for harvest by late September; excellent in fall soil.
Mâche (Valerianella locusta)
Extremely cold-hardy salad green; sow now and it will overwinter under snow, ready to pick in spring or late fall.
Garlic (Allium sativum, hardneck varieties 'German Extra Hardy' or 'Chesnok Red')
Plant individual cloves 5 cm deep, 15 cm apart, in well-draining soil amended with compost. Needs cold winter dormancy; plant by mid-September for best results.
Start indoors now
Microgreens (any fast variety: radish, mustard, broccoli)
Start on a sunny windowsill in shallow trays; ready to harvest in 10–14 days. Extends your harvest indoors as outdoor season closes.
Sprouts (mung bean, alfalfa, lentil)
Jar-sprouting requires no soil or light; ready in 3–7 days. Ideal for Thompson's long, dark winters.
Harvest now
Tomatoes (all remaining fruit)
Pick all green and partially ripe tomatoes before the first frost. Ripen indoors on a windowsill or in a paper bag; they'll mature over 2–3 weeks.
Peppers (sweet and hot)
Harvest all peppers now, even green ones; plants won't produce more before frost. Store in a cool place or process for preservation.
Squash and pumpkins (winter varieties)
Cut with 5 cm of stem attached; cure in a warm, dry spot for 10 days before storage. Check for soft spots and discard damaged fruit.
Carrots, beets, and root crops
Dig now while soil is still workable; roots store best in cool, humid conditions (near 0°C, high humidity). Leave soil on roots until storage.
Tasks this week
- Stop fertilizing perennials and shrubs now; excess nitrogen delays hardening-off and increases frost damage.
- Drain and store garden hoses; shut off outdoor water lines to prevent freeze damage.
- Mulch perennial beds with 5–8 cm of compost or aged bark after the first hard frost (watch for Oct 1); this protects roots and prevents frost heave.
- Pull spent annuals and brassicas; compost disease-free material or leave as winter mulch for soil life.
- Sow cover crops (winter rye, hairy vetch) on empty beds to prevent erosion and build soil nitrogen for spring.
Watch out for
- Early frost risk: Nighttime lows of 7–10°C this week won't kill frost-tender plants yet, but Oct 1 is your deadline. Have frost cloth or row covers ready.
- Wet soil: 20+ mm rain forecast Sept 8–9 will make soil soggy; avoid walking on beds or working soil until it dries.
- Slugs and snails thrive in cool, damp conditions. Hand-pick in early morning or use beer traps; they're most active before hard frost.
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