What to Plant Each Month: Southern Hemisphere Gardening Guide
This planting calendar helps gardeners in the Southern Hemisphere determine exactly which vegetables, herbs, and fruits to sow or transplant each month of the year. Because the Southern Hemisphere's seasons are reversed relative to the Northern Hemisphere — spring runs September–November, summer December–February, autumn March–May, and winter June–August — standard Northern calendars are useless. The core principle is simple: Last Frost Date + Days to Maturity = Latest Safe Sowing Date. Use this tool whenever you're planning a vegetable patch in Australia, New Zealand, South Africa, Argentina, Chile, or southern Brazil, and need month-by-month guidance aligned to your actual climate.
When to use this calculator
- A Melbourne home gardener planning their spring vegetable patch and needing to know which tomato and zucchini varieties to start indoors in September vs. direct-sow in October.
- A New Zealand smallholder in Christchurch scheduling successive sowings of lettuce, brassicas, and root vegetables through the autumn months of March, April, and May.
- A South African gardener in Cape Town (Mediterranean climate) timing winter brassica sowings (kale, broccoli, cauliflower) correctly for the June–August cool, wet season.
- An Argentine gardener in Buenos Aires coordinating seed-starting for warm-season crops like corn, beans, and capsicum ahead of the October–November planting window.
- A beginner gardener in Sydney who purchased seeds with Northern Hemisphere date labels and needs to convert and apply correct Southern Hemisphere sowing months.
Example calculation
- October
- Tomato, zucchini, bell pepper, capsicum, squash
How it works
4 min readHow It's Calculated
The planting calendar is built on three agronomic variables cross-referenced against reversed Southern Hemisphere seasons:
Planting Window = [Last Frost Date] to ([First Frost Date] − Days to Maturity)
Soil Temperature Threshold: warm-season crops require ≥ 18 °C (65 °F) soil temp
cool-season crops tolerate 7–18 °C (45–65 °F) soil temp
Reverse Season Offset: Southern Month = Northern Month + 6 (mod 12)
Example: Northern April sowing → Southern October sowingEach crop is classified by its minimum soil temperature for germination, its frost tolerance (hardy, half-hardy, tender), and its days to maturity (DTM). Recommendations per month combine all three factors against typical Southern Hemisphere climate zones.
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Reference Table: Monthly Planting Guide (Southern Hemisphere)
| Month | Season | Sow / Plant Outdoors | Start Indoors (4–6 wks early) | Avoid |
|---|---|---|---|---|
| January | Midsummer | Beans (bush), cucumber, basil, sweet corn | — | Frost-sensitive in cool zones |
| February | Late summer | Autumn lettuce, radish, beets, Chinese cabbage | Broccoli, cauliflower seedlings | Heavy summer crops |
| March | Early autumn | Spinach, kale, peas, silverbeet, onion seeds | Cabbage, broccoli | Tomatoes, peppers |
| April | Mid-autumn | Broad beans, garlic cloves, winter lettuce, parsley | — | Any frost-tender crop |
| May | Late autumn | Garlic, shallots, winter peas, leeks | — | Warm-season crops |
| June | Early winter | Overwintering onions, garlic, fava beans | — | Most vegetables (cold zones) |
| July | Midwinter | Bare-root fruit trees, asparagus crowns | Tomatoes, peppers (heated greenhouse) | Direct-sow tender crops |
| August | Late winter | Peas, broad beans, spinach, onion sets | Tomatoes, eggplant, peppers | Squash, corn (too cold) |
| September | Early spring | Lettuce, radish, carrots, beetroot, peas | Tomatoes, capsicum, basil | Corn (still risky) |
| October | Mid-spring | Tomatoes, zucchini, bell pepper, squash, beans | Sweet corn, pumpkin | Hardy winter crops |
| November | Late spring | Sweet corn, cucumber, pumpkin, watermelon, basil | — | Cool-season crops (bolting risk) |
| December | Early summer | Bush beans, cucumber, basil, zucchini (succession) | — | Brassicas (heat stress) |
DTM reference ranges: Tomatoes 60–85 days; Zucchini 45–65 days; Broccoli 80–100 days; Peas 55–70 days; Garlic 240–270 days from clove planting.
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Typical Cases with Real Numbers
Case 1 — October in Melbourne (temperate, ~37°S)
A gardener wants to grow 'Roma' tomatoes (DTM: 75 days) and 'Black Beauty' zucchini (DTM: 55 days). Average last frost in Melbourne is around August 20. Soil reaches 18 °C by mid-October.
Case 2 — April in Christchurch, NZ (cool temperate, ~43°S)
First autumn frost typically arrives late May. A gardener wants to sow broad beans (DTM: 85 days) and winter spinach (DTM: 40 days, frost-hardy).
Case 3 — July in Cape Town (Mediterranean, ~33°S)
Cape Town's mild winters (rarely below 5 °C) allow year-round gardening. July is peak cool season.
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Common Mistakes
1. Using a Northern Hemisphere calendar without offsetting by 6 months. The most frequent beginner error. A seed packet saying "sow April–June" means September–November in the Southern Hemisphere. Always apply the +6 month rule.
2. Planting warm-season crops by calendar date instead of soil temperature. Tomatoes sown in soil below 15 °C will germinate poorly or rot. Use a soil thermometer — wait for ≥ 18 °C consistently, regardless of the month.
3. Ignoring local altitude and latitude variation. Gardeners in Johannesburg (1,750 m elevation) experience frosts in June–July despite a subtropical latitude. A gardener in Darwin, Australia (~12°S) has no frost risk at all and can grow warm-season crops nearly year-round.
4. Sowing cool-season crops too late in autumn. Brassicas like broccoli need 80–100 days — if sown in June in a cold-winter zone (e.g., Dunedin, NZ), they won't mature before repeated hard frosts destroy them. The window closes by late April.
5. Planting garlic at the wrong time. Garlic requires a cold vernalization period (below 10 °C for 4–8 weeks) to bulb properly. In most Southern Hemisphere zones, plant cloves April–June — not spring — for harvest the following November–December.
6. Confusing "sow" with "transplant" dates. Starting tomatoes indoors in August (late winter) for a September–October outdoor transplant is correct. Directly sowing tomatoes outdoors in August will fail in most temperate zones due to cold soil.
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Related Calculators
Frequently asked questions
Why is the Southern Hemisphere planting calendar exactly 6 months off from the Northern Hemisphere?
Because Earth's axial tilt (23.5°) means the Southern Hemisphere receives maximum solar radiation in December–January and minimum in June–July — the precise opposite of the Northern Hemisphere. This creates a full 6-month seasonal offset. A Northern Hemisphere 'plant in May' instruction becomes 'plant in November' below the equator. This offset is consistent across all latitudes in the Southern Hemisphere, though the intensity of seasons varies by distance from the equator.
What soil temperature do tomatoes need to germinate successfully?
Tomatoes require a minimum soil temperature of 15 °C (60 °F) for germination, but the optimal range is 21–27 °C (70–80 °F), where germination occurs in 5–7 days. Below 15 °C, germination can take 2–3 weeks or seeds may rot before sprouting. USDA plant hardiness guidelines and agricultural extension services consistently recommend waiting until soil reaches 18 °C for reliable outdoor tomato germination in the Southern Hemisphere spring (October–November in temperate zones).
Can I grow warm-season vegetables year-round in tropical parts of the Southern Hemisphere (e.g., Darwin, Australia or northern Brazil)?
Yes. Tropical zones within the Southern Hemisphere (latitudes roughly 0–15°S) experience minimal seasonal temperature variation and no frost risk. In Darwin, Australia, the main constraint is the wet season (November–April), which brings high humidity and disease pressure that limits some crops. The dry season (May–October) is ideal for most vegetables. Crops like tomatoes, beans, cucumbers, and capsicum can be grown almost year-round with irrigation management during the dry season.
When should I plant garlic in the Southern Hemisphere?
Plant garlic cloves in April through June (autumn to early winter) across most Southern Hemisphere temperate zones. Garlic requires a cold vernalization period — exposure to temperatures below 10 °C for 4–8 weeks — to trigger bulb formation. Without this cold period, garlic grows as a leaf only, producing little or no bulb. Days to maturity from planting are approximately 240–270 days, meaning April-planted garlic is typically harvested November–December when foliage yellows and falls over.
How does altitude affect the Southern Hemisphere planting calendar?
Altitude reduces temperature by approximately 6.5 °C per 1,000 meters of elevation (the standard atmospheric lapse rate, per NOAA). A gardener in Johannesburg (elevation ~1,750 m) experiences temperatures roughly 11 °C cooler than sea-level locations at the same latitude. This means frost risk in June–July, delayed spring soil warming, and a compressed warm-season planting window compared to coastal zones at the same latitude. Always adjust your planting window by checking local frost date records rather than relying solely on latitude.
What is the difference between 'frost-hardy,' 'half-hardy,' and 'tender' crops — and which belong to which category?
Frost-hardy crops survive repeated frosts (down to −5 °C or lower): kale, broad beans, garlic, spinach, peas, parsnips, Brussels sprouts. Half-hardy crops tolerate light frosts (down to −2 °C briefly): broccoli, cauliflower, carrots, beetroot, lettuce. Tender crops are killed by any frost and need soil above 15 °C: tomatoes, peppers, cucumbers, zucchini, sweet corn, basil, eggplant. This classification determines whether a crop can be planted in early spring/late autumn or must wait for frost-free conditions.
How do I calculate the latest date I can plant a crop before the first autumn frost?
Use the formula: Latest Sow Date = First Autumn Frost Date − Days to Maturity − 14 days (buffer). For example, if your first frost in Christchurch, NZ is May 25, and you want to grow zucchini (DTM: 55 days), calculate: May 25 − 55 days − 14 days = approximately March 27. This means your last safe direct-sow date for zucchini is around late March. The 14-day buffer accounts for harvest time and unexpected early cold snaps. Historical frost date records for New Zealand are maintained by NIWA (National Institute of Water and Atmospheric Research).
Which months are best for sowing leafy greens (lettuce, spinach, silverbeet) in temperate Southern Hemisphere climates?
Leafy greens have two main sowing windows in temperate Southern Hemisphere zones (e.g., Melbourne, Wellington, Cape Town): late summer to autumn (February–April) for a winter harvest, and early spring (August–October) for a spring/early-summer harvest. Avoid the hottest months (December–January) as most lettuce varieties bolt (go to seed) when daytime temps exceed 25 °C. Spinach and silverbeet are more heat-tolerant but still perform best below 28 °C. Succession sow every 3–4 weeks within the window for a continuous harvest.
Do seed packet instructions from US or European brands apply to Southern Hemisphere gardeners?
Not directly. US and European seed packets list Northern Hemisphere sowing months. To convert, add 6 months to every date listed. A packet saying 'sow March–May, transplant May–June' means 'sow September–November, transplant November–December' in the Southern Hemisphere. Additionally, some climate-specific advice (e.g., 'plant after Memorial Day') is regionally irrelevant. Always cross-reference with local agricultural extension resources such as Agriculture Victoria, NZ's Yates Garden Guide, or South Africa's Farming Portal for locally validated planting windows.