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September planting calendar

autumn

What to plant in September

Autumn arrives. Zones 3-7 race to plant fall greens and garlic; zones 8-10 enjoy a second growing season as heat eases. The fall garden window is open across the US and UK.

Universal September tasks

These tasks apply to most temperate gardens across the US and UK in September. Check the per-zone sections below for the specific crops to plant in your zone.

UK gardeners — September

September starts the UK's autumn garden. Sow winter salad, spring cabbage, mustard, mizuna, and overwintering onions. Plant garlic and overwintering broad beans late month. Harvest apples, pears, plums, sweetcorn, and main-crop potatoes.

Most of England and Wales falls in RHS H4-H5 (roughly USDA 7-8). Scotland skews cooler (H3-H4); coastal southwest skews warmer (H5). See UK hardiness ratings →

September planting by USDA zone

Pick your USDA zone for the full crop-by-crop list for September. Each zone page includes sowing, transplanting, harvesting, and maintenance actions.

Zone 3 — September

4 actions
  • Sow outdoors: Garlic (mid- to late September)
  • Harvest: Tomatoes (before first frost), peppers, winter squash, pumpkins, onions, potatoes
  • Sow outdoors: Cover crops — winter rye, oats, peas

See full zone 3 plan →

Zone 4 — September

4 actions
  • Sow outdoors: Garlic (late September to early October)
  • Sow outdoors: Spinach, mache, lettuce (overwintering)
  • Harvest: Tomatoes (final), winter squash, pumpkins, apples, onions, potatoes

See full zone 4 plan →

Zone 5 — September

4 actions
  • Sow outdoors: Spinach, mache, lettuce, radishes, kale (cold-hardy varieties)
  • Sow outdoors: Garlic (late September into October)
  • Harvest: Tomatoes, peppers, winter squash, pumpkins, apples, beans, onions

See full zone 5 plan →

Zone 6 — September

4 actions
  • Sow outdoors: Spinach, mache, lettuce, radishes, turnips, kale, mustard greens
  • Transplant: Last brassica transplants for fall
  • Harvest: Tomatoes, peppers, winter squash, pumpkins, apples, sweet potatoes, beans

See full zone 6 plan →

Zone 7 — September

4 actions
  • Sow outdoors: Spinach, lettuce, kale, mustard, radishes, turnips, carrots, beets, peas
  • Transplant: Fall brassicas, lettuce, kale
  • Harvest: Tomatoes, peppers, okra, sweet potatoes, winter squash, peanuts

See full zone 7 plan →

Zone 8 — September

4 actions
  • Sow outdoors: Lettuce, spinach, kale, mustard, radishes, peas, beets, carrots
  • Transplant: Brassica transplants, lettuce, kale, collards
  • Harvest: Fall tomatoes (starting), okra, sweet potatoes, southern peas

See full zone 8 plan →

Zone 9 — September

4 actions
  • Transplant: Fall tomato, pepper, and brassica transplants
  • Sow outdoors: Lettuce, spinach, kale, mustard, peas, carrots, beets, radishes
  • Harvest: Sweet potatoes, okra, southern peas, hot peppers, citrus (early)

See full zone 9 plan →

Zone 10 — September

4 actions
  • Transplant: Fall tomatoes, peppers, eggplant
  • Sow outdoors: Cool-season crops opening — lettuce, kale, broccoli transplants, carrots, beets
  • Harvest: Tropical fruit, citrus, sweet potatoes, hot peppers

See full zone 10 plan →

Zones 1-2 and 11-13 in September

Sub-Arctic zones 1-2 (interior Alaska and northern Canada) are still effectively dormant for any month outside June-August. Greenhouse and cold-frame work dominates the calendar; outdoor planting compresses into a 60-90 day window.

Tropical zones 11-13 (Hawaii, southern Florida, Puerto Rico) have no frost cycle. Calendar timing depends on the wet/dry seasons rather than spring/fall frost — most temperate crops grow October through April, with the hot-wet summer as the off-season.

Source and methodology

Timing curated against US Cooperative Extension publications (UNL, UMN, NC State, Texas A&M, UF/IFAS, Oregon State) and cross-checked against the RHS sowing calendar for UK readers. Frost-date averages from NOAA Climate Data Online. Curated by the Growli editorial team.

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