December · USDA Zone 4
winterWhat to plant in December in USDA zone 4
Winter planting guide for zone 4 (Northern Maine, northern Wisconsin, Montana, parts of New England) — a 125-day growing season with last frost around mid-May and first frost around mid-September.
Maintenance in December — zone 4
- Check stored crops, garlic mulch, perennial cover
- Houseplants — slow watering for winter dormancy
Prep and planning — zone 4
- Garden plan and seed orders
- Dormant pruning on mild dry days
Universal December tasks
These apply across most US and UK gardens in December, regardless of zone.
- Review this year's garden journal — what worked, what didn't, what to change.
- Start your seed list for next year while pleasure and pain are fresh.
- Check stored crops weekly for rot — winter squash, onions, garlic, potatoes.
- Force amaryllis and paperwhite bulbs for indoor color.
- Tend houseplants — many slow-grow now, so reduce watering by half.
- Prune dormant fruit trees and grapes on a dry, mild day.
Why this works for zone 4
Zone 4 has average annual minimum temperatures of -30 to -20°F (-34 to -29°C) and a frost-free window from mid-May to mid-September — about 125 growing days. Tomatoes and peppers benefit from row covers in early season. Mulch heavily over winter for perennials and garlic.
Dates are zone-wide averages. Local microclimates (south-facing slopes, urban heat, lakeside warmth, elevation) can shift the window by 1-2 weeks within the same zone.
UK gardeners — December
December is the UK's quiet month. Harvest brussels sprouts, leeks, parsnips, kale, and overwintered chard. Plant bare-root fruit trees and bushes on mild days. Force rhubarb crowns indoors. Plan next year and order seeds.
Source and methodology
Frost-date averages from NOAA Climate Data Online within USDA zone 4. Hardiness boundaries from the USDA Plant Hardiness Zone Map (2023). Crop timing curated against US Cooperative Extension Service publications (UNL, UMN, NC State, Texas A&M, UF/IFAS, Oregon State) and cross-referenced against the RHS sowing calendar. Curated by the Growli editorial team.
Keep going
- ← November in zone 4
- January in zone 4 →
- All zones — what to plant in December
- USDA Zone 4 — frost dates and crop list
- Full 12-month planting calendar