Fall · September 8, 2026

Kingston, Ontario

Great Lakes & St. Lawrence Lowlands·Hardiness zone 5b

Now

23°C · Overcast

Today

23° / 12°

Soil 6 cm

19°C

First frost

~54 days (Nov 1)

Gardening in Kingston

AI field guide · refreshed weekly

Kingston Gardening: Early Fall Planting & Harvest Window

Zone 5b means your first fall frost arrives around November 1—you have 54 days left to grow cool-season crops. Soil at 19°C is ideal for fall seeding; it'll drop steadily through October. Spring frost (April 26) is 135 days behind you, so summer crops are done.

Sow outdoors now

  • Spinach (Bloomsdale, Space or Tyee)

    Direct seed now; germinates fast at 19°C soil and matures in 40–50 days before hard frost. Space 10 cm (4 in) apart in full sun or part shade.

  • Arugula (Roquette)

    Sow every 2 weeks through mid-September for continuous harvest. Thrives in cool weather and ready in 30 days; thin to 15 cm (6 in).

  • Radish (Cherry Belle, French Breakfast)

    Matures in 25–30 days at this soil temperature. Sow in succession; works well interplanted with slower crops to break up soil.

  • Mâche (Corn Salad)

    A cold-hardy green that germinates at 19°C and overwinters in zone 5b under mulch. Sow densely, thin to 10 cm (4 in).

  • Garlic (hardneck varieties: German Extra Hardy, Chesnok Red)

    Plant cloves 5 cm (2 in) deep, 15 cm (6 in) apart, in well-draining soil by late September. Mulch heavily after soil freezes to prevent heave.

Start indoors now

  • Kale (Winterbor, Lacinato)

    Start seeds indoors now for transplant in 3–4 weeks; these varieties tolerate hard frost and improve in flavor after a freeze. Needs 12–14 hours light.

  • Cabbage (January King, Tundra)

    Sow indoors for fall transplant; both are cold-hardy and store well. Transplant in 4 weeks when soil is still warm enough for establishment.

  • Broccoli (Waltham 29, De Cicco)

    Start now for October transplant; these mature before hard frost and tolerate light freezes. Needs consistent moisture after transplant.

Harvest now

  • Tomatoes (all varieties)

    Pick all remaining fruit before the first hard frost (Nov 1). Green tomatoes ripen indoors at room temperature in 2–3 weeks.

  • Beans & Peas (bush types)

    Harvest regularly to encourage final flushes. Most will finish by late September as nights cool.

  • Squash & Pumpkins

    Cut with 5 cm (2 in) stem; cure in a warm, dry place for 2 weeks before storage. Check for soft spots or damage.

  • Herbs (basil, cilantro, parsley)

    Cut heavily before frost kills tender annuals. Dry or freeze for winter use; hardy parsley will regrow next spring.

Tasks this week

  • Clean up spent summer crops and add disease-free material to compost; remove any with blight or mildew.
  • Mulch beds with 5–7 cm (2–3 in) of shredded leaves or straw to insulate soil and suppress weeds through fall.
  • Water newly seeded beds gently and consistently; September rain is unreliable—check soil moisture daily.
  • Scout for late-season pests (cabbage moths, aphids) on brassicas and greens; hand-pick or use neem oil if needed.
  • Divide and transplant spring-blooming perennials (daylilies, coneflowers) while soil is still warm and moist.

Watch out for

  • Frost can arrive earlier than November 1 in low-lying areas or near water—monitor forecasts closely after mid-October.
  • Powdery mildew thrives in cool, humid September nights; ensure good air circulation and avoid overhead watering.
  • Slugs and snails are active in damp fall weather—use beer traps or hand-pick at dusk, especially around new seedlings.

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