Why December is Ideal for Garden Planning
December might seem an odd time for serious garden planning when heat slows outdoor activity. However, this is precisely when next year’s success gets determined. Seed companies have full stock before popular varieties sell out. Beds can rest, receive amendments, or grow green manures. Summer’s warmth accelerates soil building processes. Planning now prevents scrambling in February when actual planting windows open.
The combination of downtime for physical garden work and peak availability from seed suppliers makes December the strategic planning month. Use this period to secure seeds, map crop rotations, and prepare soil while high temperatures limit intensive outdoor labour.
December Seeds to Order for the Year Ahead
December is when you lock in what you’ll grow throughout 2026. Popular heirloom varieties from Australian seed companies sell out early. Unusual varieties disappear fast. Ordering now ensures you get exactly what you want rather than settling for whatever remains in March.
Summer and Early-Autumn Crops
Tomatoes
Order tomato seeds now for sowing from late summer through early autumn depending on your region. Southern growers sow September-October for December-February harvests. Northern growers sow February-March for dry season production.
Heirloom varieties require forward planning as specialist seed companies stock limited quantities. Popular varieties like Black Russian, Mortgage Lifter, and Cherokee Purple sell out quickly. If you’re growing for sauce or preserving, order paste tomato varieties including Roma, San Marzano, or Amish Paste.
Capsicums and Chillies
Both require long, warm growing seasons. Southern growers sow September-October. Northern growers sow March-April for dry season crops. Capsicums need 100-150 days from transplanting to first harvest. Chillies mature slightly faster but benefit from extended growing seasons for heavy production.
Order specific heat levels for chillies now. Mild varieties including Hungarian Wax or Banana suit general cooking. Medium heat jalapeños and serranos work for most applications. Hot varieties including cayenne, Thai, and habanero require dedicated use planning.
Eggplants
Eggplants demand warm soil and long seasons. Sow September-October in southern regions, February-March in northern areas. White, purple, and Asian varieties all need ordering by December as selections diminish rapidly.
Pumpkins
Pumpkins sow in spring across most regions for autumn harvest. Queensland and Northern Territory growers plant during early wet season for dry season harvest. Varieties range from compact bush types to sprawling heirlooms. Queensl and Blue, Jarrahdale, and Butternut all need space planning now to ensure adequate growing room next season.
Cucumbers and Zucchini
Both are vigorous warm-season crops. Order seeds in December for spring sowing across southern states or late summer sowing in tropical regions. Lebanese, Apple, and Continental cucumber varieties suit different uses. Zucchini varieties including Blackjack, Costata Romanesco, and Golden perform differently in various climates.
Basil and Other Warm Herbs
Basil, coriander (for tropical areas), Vietnamese mint, and other warm-season herbs need advance ordering. Sweet basil remains most popular, but Thai, Holy, and Lemon basil varieties offer culinary diversity. Order now to secure specific varieties before spring rush.
Cool-Season Staples
Broccoli, Cauliflower, and Cabbage
These brassicas require precise timing. Order seeds in December for autumn sowing (March-May depending on region). Sowing windows are tight. Miss them and you lose the entire season.
Broccoli varieties mature at different rates. Early varieties ready 60-70 days from transplanting. Late varieties need 90-100 days. Cauliflower similarly ranges from 65 days to 100+ days. Planning which varieties to sow when requires having seeds on hand before sowing windows open.
Spinach
True spinach grows best in cool weather. Order seeds now for autumn sowing (March-May). Varieties differ in bolt resistance. Bloomsdale and Perpetual spinach handle variable temperatures better than other types.
Peas
Peas sow from autumn through winter depending on location. Snow peas, sugar snap, and shelling peas all need different trellis systems and harvest timing. Order seeds in December to ensure availability when your specific sowing window opens.
Root Crops
Carrots
Carrots sow year-round in many Australian regions with variety selection determining success. Amsterdam, Nantes, and Chantenay types suit shallow or rocky soils. Imperator types need deep, loose soil. Order specific types matching your soil conditions rather than generic packets.
Beetroot
Beetroot handles a wide temperature range. Order cylindrical, round, and golden varieties for succession planting through cooler months. Detroit Dark Red remains reliable, but Chioggia adds visual interest with red and white rings.
Onions
Onion seeds or seedlings plant from autumn through winter depending on day-length response. Long-day varieties suit southern regions. Short-day varieties work in tropical areas. Order correct types for your latitude. Seed companies stock regional recommendations.
Potatoes (Seed Tubers)
Certified seed potatoes order now for autumn delivery. Autumn planting (March-May) suits most regions. Sebago, Desiree, and Pontiac remain popular, but fingerling and coloured varieties add diversity. Seed potatoes sell out quickly once planting season approaches.
Perennials and Long-Game Crops
Asparagus
Asparagus crowns plant in late winter through early spring. Order crowns in December for delivery at planting time. Male varieties including Jersey Knight and Jersey Supreme produce heavier yields than older varieties. Allow 2-3 years for first harvest after planting.
Rhubarb
Rhubarb crowns plant autumn through winter depending on region. Cooler climates suit rhubarb better than tropical areas. Victoria and Crimson Red produce reliably. Order crowns now for winter delivery and planting.
Artichokes
Globe artichokes grow as perennials in most Australian climates. Green Globe remains most common, but Purple varieties offer different flavours. Sow seeds autumn through winter or plant divisions. December ordering ensures stock availability.
Berries and Fruit Tree Rootstocks
Bareroot berry canes and fruit trees ship during dormancy (June-August). However, orders taken from December onwards secure varieties before stock depletes. Raspberries, blackberries, blueberries, and fruiting trees all require pre-ordering months ahead for winter delivery.
Seeds You Can Sow in December
While planning focuses December activities, some crops actually sow now in Australian conditions.
Northern Australia
December sowing for tropical and subtropical regions offers excellent opportunities for heat-loving crops.
Okra: Thrives in heat and humidity. Direct sow now for January-March harvests.
Sweet potato slips: Plant slips now at wet season start for dry season harvest.
Basil: Establishes quickly in warm soil. Successive sowings every 4 weeks ensure continuous supply.
Snake beans: Vigorous climbers producing through hot weather. Sow now for extended harvests.
Rosella: Sow December-January for April-May harvest. Hibiscus relative producing calyces for jams and drinks.
Luffa: Vigorous vine producing edible young fruit and mature sponges. Needs strong trellis and full wet season to mature.
Chillies: Year-round growing possible in tropics. December sowings produce through dry season.
Southern Australia
December sowing for temperate regions focuses on fast-growing summer crops.
Zucchini: Fast-growing in heat. December sowings produce February-March harvests.
Cucumbers: Establish on trellis quickly. Succession plant every 3 weeks through January.
Beans: Both bush and climbing beans sow through December-January for summer harvests.
Sweet corn: Early varieties only. Sow now for March-April harvests. Later sowings risk autumn frosts before maturity.
Herbs: Basil, chives, and coriander (with shade) all establish in December. Water consistently.
Arid and Inland Regions
December sowing for hot, dry climates capitalises on heat tolerance.
Melons: Watermelon, rockmelon, and honeydew all thrive in dry heat. Need consistent deep watering.
Pumpkins: Long-season varieties sow now for autumn harvests before first frosts.
Heat-tolerant greens: Malabar spinach and amaranth handle extreme heat other greens can’t tolerate.
Creating Your December Seed List for 2026 Crops
Start with What Worked This Year
Review this year’s successes and failures before ordering new seeds. Which varieties produced heavily? What suffered disease problems? Which crops suited your soil and water availability?
Yield assessment: Note which varieties delivered best harvests. Cherry tomatoes might have outproduced beefsteak types. Climbing beans possibly yielded more than bush varieties in your space.
Disease resistance: Some varieties resist problems prevalent in your area. If you faced tomato blight, order resistant varieties. Powdery mildew on zucchini suggests selecting resistant cultivars.
Soil performance: Carrots struggling in clay soil indicate need for short-rooted varieties. Successful crops in your specific soil get priority reordering.
Water requirements: Drought-sensitive crops might not suit your water availability. Reorder varieties proven to handle your watering schedule.
Add One or Two New Experiments
Don’t completely overhaul your garden plan. Add 1-2 experimental crops or varieties alongside proven performers.
New heirloom varieties: Australian seed companies stock hundreds of heirloom vegetables. Add one new tomato, bean, or lettuce variety to test alongside reliable favourites.
Climate-resilient lines: Varieties bred for heat tolerance, drought resistance, or humidity all expand options as climate variability increases.
Crops for specific seasons: Try vegetables utilising your specific growing conditions. Long hot summers suit melons and eggplants. Mild winters allow extended brassica seasons.
Plan for Succession Planting
Different maturity rates enable continuous harvests rather than overwhelming gluts.
Quick crops (30-45 days):
- Radish
- Lettuce
- Pak choy
- Asian greens
Sow these every 2-3 weeks through appropriate seasons. Small plantings provide steady supply without waste.
Medium crops (60-80 days):
- Beans
- Beetroot
- Carrots
- Zucchini
Stagger plantings 3-4 weeks apart. This extends harvests and prevents simultaneous maturity.
Long crops (90-150 days):
- Tomatoes
- Pumpkins
- Sweet corn
- Capsicums
Plant these once or twice per season with varieties having different maturity dates.
December Bed Preparation for Next Year’s Crops
Soil preparation now determines success for autumn and winter plantings.
Clear Old Crops and Remove Disease Risks
Pull finished summer crops including spent tomatoes, zucchini, and cucumbers. Remove all plant material showing disease symptoms. Don’t compost diseased plants as many pathogens survive composting temperatures.
Solarisation for persistent problems:
If beds suffered significant disease this year, solarise now. Water soil deeply, cover with clear plastic, and seal edges. Leave 4-6 weeks during peak heat. Temperatures under plastic reach 50-60°C, killing many pathogens, weed seeds, and pest eggs.
Top Up the Soil
Add organic matter now while beds rest. This improves structure, moisture retention, and nutrient availability for next plantings.
Compost additions:
Spread 5-10cm of well-aged compost over beds. Fork through top 15-20cm of soil. Compost adds nutrients and beneficial microbes while improving soil structure.
Well-rotted manure:
Aged cow, horse, or chicken manure adds nitrogen and organic matter. Chicken manure needs thorough aging (6+ months) before use. Fresh manure burns plants and introduces weed seeds.
pH testing:
Test soil pH if planning brassicas (prefer 6.5-7.0) or acid-loving crops. Simple pH kits cost $10-20 from nurseries. Add lime if pH below 6.0 for most vegetables. Add sulphur if pH above 7.5.
Rest Beds Under Mulch
December’s heat and dry conditions stress unprotected soil. Mulching protects soil structure and maintains beneficial organisms.
Suitable mulches:
- Lucerne hay (adds nitrogen as it breaks down)
- Pea straw (weed-free and breaks down over months)
- Sugar cane mulch (neutral, long-lasting)
- Aged wood chips (suitable for paths and permanent beds)
Apply 7-10cm depth over beds. Keep mulch clear of plant stems where applicable. Heavy mulch moderates soil temperature, reducing stress on soil organisms.
Shade cloth for extreme heat:
In areas experiencing 40°C+ temperatures, shade cloth over empty beds prevents soil degradation. 50% shade cloth on temporary frames protects soil microbes and structure during extreme heat.
Water deeply weekly:
Even empty beds benefit from deep watering once weekly. This maintains soil moisture supporting beneficial organisms. Deep watering prevents soil from becoming hydrophobic, which makes rewetting difficult when planting resumes.
Green Manures
Summer green manures build nitrogen and organic matter while controlling weeds.
Summer green manure options:
- Sunn hemp: Deep rooted, adds significant nitrogen, grows quickly in heat
- Millet: Fast-growing, adds organic matter, tolerates dry conditions
- Cowpea: Nitrogen-fixing legume, handles heat and humidity
- Lab lab: Vigorous nitrogen-fixer suited to northern regions
Sow green manures into prepared beds. Allow 6-10 weeks growth. Cut down before flowering. Either incorporate immediately or leave as surface mulch. Wait 2-3 weeks before planting crops to allow breakdown.
Planning Your Crop Rotation
Rotation reduces disease buildup and pest pressure while balancing soil nutrient demands.
Four-Category Rotation System
Organise crops into four main families:
- Fruiting crops: Tomatoes, capsicums, eggplant, cucurbits
- Leafy crops: Lettuce, spinach, Asian greens, brassicas
- Root crops: Carrots, beetroot, radishes, turnips
- Legumes: Beans, peas, lupins
Rotate each bed through categories annually. This prevents same-family diseases building in soil. Tomatoes followed by tomatoes in the same bed invite disease. Tomatoes followed by brassicas, then root crops, then legumes completes healthy four-year cycle.
Simple Rotation Examples
Two-bed garden:
- Year 1: Bed A = Tomatoes + basil, Bed B = Lettuce + beans
- Year 2: Bed A = Lettuce + beans, Bed B = Tomatoes + basil
Three-bed garden:
- Year 1: Bed A = Tomatoes, Bed B = Brassicas, Bed C = Root vegetables
- Year 2: Bed A = Brassicas, Bed B = Root vegetables, Bed C = Tomatoes
- Year 3: Bed A = Root vegetables, Bed B = Tomatoes, Bed C = Brassicas
Four-bed garden:
- Year 1: Bed A = Fruiting, Bed B = Leafy, Bed C = Roots, Bed D = Legumes
- Rotate each bed to next category annually
Map your rotation plan in December before spring planting begins. This prevents accidental same-family plantings in same locations.
Water Planning for Next Season
December heat highlights water system weaknesses. Plan improvements now for implementation before next summer.
Drip Irrigation Installation
Drip systems deliver water directly to root zones, reducing waste. Install during quiet December period before spring planting surge. Calculate water needs per bed. Size systems appropriately for planned crops.
Oversized Mulch Zones
Identify beds needing heavier mulching. High-water-demand crops including tomatoes, cucumbers, and leafy greens benefit from 10-15cm mulch depth. Drought-tolerant crops manage with 5-7cm.
Tanks and Water Harvesting
December storms in many regions offer water capture opportunities. Plan tank installations, swale locations, or diversion systems before next wet season. Even small tanks (1,000-2,000 litres) provide backup for critical periods.
Positioning Crops by Water Demand
Group high-water vegetables together. This allows targeted irrigation without overwatering drought-tolerant crops. Position near water sources or on flat ground where irrigation is simplest.
Common December Mistakes
Leaving Seed Orders Too Late
Popular varieties sell out. Procrastination until March means settling for whatever remains. December ordering guarantees choice selection.
Starting Cool-Season Crops in Heat
Enthusiasm sometimes overrides climate reality. Broccoli, cauliflower, and snow peas don’t sow in December heat across most of Australia. These wait for autumn. Sowing now wastes seeds and space.
Over-Tilling Dry Soil
Working rock-hard dry soil creates dust and damages structure. Wait until soil has moisture. Light forking of top layer suffices. Deep digging dry soil does more harm than good.
Adding Fresh Manure Close to Planting
Fresh manure burns plants and introduces weed seeds. Age manure 6+ months before use. Alternative: add fresh manure now to beds not planting until March-April. This allows decomposition time.
Forgetting to Map Beds
Planting without crop rotation planning leads to disease problems. Map where each crop grew this year. Plan next year’s layout avoiding same families in same beds.
Simple December Garden Checklist
Essential December tasks to complete before year end:
- Order seeds from Australian suppliers before varieties sell out
- Map next year’s garden layout including crop rotation
- Build or repair garden beds needing structural work
- Refresh mulch on all beds, empty or planted
- Sow green manure crops into resting beds
- Plant heat-loving crops suitable for your region
- Plan irrigation system upgrades for implementation before next summer
- Clear and dispose of disease-affected plant material
- Test and amend soil pH if planning pH-sensitive crops
Planning for Success
December planning sets foundations for successful 2026 gardens. Seed ordering while full selection remains available ensures you grow exactly what you want. Bed preparation during December’s heat takes advantage of high temperatures accelerating organic matter breakdown and green manure growth. Planning crop rotations and water systems now prevents scrambling when actual planting windows open.
The combination of planning activities with selected sowings for tropical regions makes December productive despite heat limiting heavy physical work. Use this month strategically. Next year’s abundance begins with December decisions.
