Fall · September 8, 2026

Greater Sudbury, Ontario

Boreal Forest & Shield·Hardiness zone 4b

Now

21°C · Overcast

Today

25° / 17°

Soil 6 cm

19°C

First frost

~37 days (Oct 15)

Gardening in Greater Sudbury

AI field guide · refreshed weekly

Sudbury Gardening: Early September – Harvest Peak, Plant for Spring

Zone 4b means 37 days until your first frost (mid-October). Soil at 19°C is still warm enough for cool-season crops but cooling fast. You're 116 days past your last spring frost, so tender annuals are now winding down. This is prime time to sow fall crops and plant spring bulbs before ground freezes in November.

Sow outdoors now

  • Spinach (Spinacia oleracea 'Space' or 'Bloomsdale')

    Sow directly now; germinates in cool soil and matures in 40–50 days before hard frost. Thin to 10 cm (4 in) apart.

  • Arugula (Eruca sativa)

    Fast crop (30 days); sow thickly in rows. Tolerates light frost and tastes better after a chill.

  • Radish (Raphanus sativus 'Cherry Belle')

    Matures in 25–30 days; sow every 2 weeks for succession harvests through October.

  • Mâche (Valerianella locusta)

    Cold-hardy salad green; sow now for winter harvests under row cover or in cold frame.

  • Garlic (Allium sativum, hardneck varieties)

    Plant individual cloves 5 cm (2 in) deep, 15 cm (6 in) apart, in well-draining soil. Mulch after ground freezes; harvest next June.

Start indoors now

  • Microgreens (any fast variety: radish, mustard, broccoli)

    Start in trays indoors for harvest in 10–14 days; extends your harvest season as outdoor beds wind down.

  • Spring bulbs (Tulipa, Narcissus, Crocus)

    Chill bulbs in the fridge for 12–16 weeks, then pot up indoors in late November for early spring blooms.

Harvest now

  • Tomatoes (all types)

    Pick all remaining fruit—both ripe and mature green—before the first frost (37 days away). Green ones ripen indoors in a paper bag.

  • Beans (bush and pole)

    Harvest regularly to encourage more pods; frost will kill plants within weeks.

  • Squash and pumpkins (Cucurbita spp.)

    Cut with 5 cm (2 in) stem; cure in a warm, dry spot for 10 days before storage.

  • Lettuce, kale, chard (cool-season crops)

    Pick outer leaves continuously; these crops improve in flavor as nights cool.

Tasks this week

  • Deadhead spent flowers to redirect energy into seed production or extend blooms on perennials.
  • Cut back perennials (coneflower, black-eyed Susan) to 15 cm (6 in) only after frost kills foliage; leave seed heads for wildlife.
  • Divide spring-blooming perennials (hostas, daylilies) now through mid-September while soil is still warm.
  • Mulch beds with 5–8 cm (2–3 in) of compost or shredded leaves to insulate roots and suppress weeds.
  • Clean up fallen leaves and debris to reduce overwintering sites for pests and disease.

Watch out for

  • Frost risk: Nights dip to 5–7°C mid-week (Sept 10–11, 13–14). Cover tender plants or harvest before then.
  • Powdery mildew and rust thrive in cool, humid conditions; improve air flow and remove infected foliage.
  • Slugs and snails peak in fall dampness; hand-pick at dusk or use beer traps in vegetable beds.

The gardening note for Greater Sudbury, every week

One email, Sunday evening. Unsubscribe anytime.