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Southern Hemisphere Planting Calendar: What to Sow Each Month

Q: When should I plant garlic in the Southern Hemisphere?

Plant garlic cloves in **April through June** (autumn to early winter) in most temperate Southern Hemisphere zones. Garlic requires cold vernalization — exposure to temperatures below 10 °C for 4–8 weeks — to trigger bulb formation. Without this cold period, garlic grows only as a leaf, producing little or no bulb. From April planting, harvest arrives approximately **November–December** (240–270 days later) when foliage yellows and falls over.

Q: How does altitude affect the Southern Hemisphere planting calendar?

Altitude reduces temperature by approximately **0.65 °C per 100 meters** of elevation (standard atmospheric lapse rate, NOAA). A gardener in Johannesburg (~1,750 m) experiences temperatures roughly 11 °C cooler than sea-level locations at the same latitude, creating frost risk in June–July and a compressed warm-season planting window. Always check local frost date records rather than relying solely on latitude. In South America, Andean zones (Mendoza, Temuco, Quito) can be 3–4 weeks behind coastal calendars.

Q: What is the difference between frost-hardy, half-hardy, and tender crops?

**Frost-hardy** crops survive repeated frosts (down to −5 °C): 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 or late autumn, or must wait for fully frost-free conditions.

Q: How do I calculate the latest date I can plant before the first autumn frost?

Use this formula: **Latest Sow Date = First Autumn Frost Date − Days to Maturity − 14 days (buffer)**. Example: if your first frost in Christchurch, NZ is May 25, and you want to grow zucchini (DTM: 55 days): May 25 − 55 days − 14 days = approximately March 27. Your last safe direct-sow date is around late March. The 14-day buffer accounts for harvest time and unexpected early cold snaps. Historical NZ frost dates are maintained by NIWA (National Institute of Water and Atmospheric Research).

Q: What is the best month to start a vegetable garden from scratch in the Southern Hemisphere?

**September or October** is the ideal starting point for most temperate Southern Hemisphere locations (Buenos Aires, Melbourne, Auckland, Cape Town). Soil temperatures rise above 15 °C, frost risk is essentially over, and the growing season ahead offers 4–5 frost-free months. Start with easy crops first: lettuce and radishes from seed (ready in 30–45 days), and tomato or zucchini seedlings purchased from a nursery (avoiding the complexity of indoor seed-starting). By January you'll have your first harvests and the confidence to plan a full year's garden.

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Reviewed by: Martín Rodríguez (política editorial ) · Last reviewed: 4 jun 2026

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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.

Last reviewed: June 3, 2026 Verified by Martín Rodríguez Source: INTA Argentina — Calendario de Siembra de Hortalizas, Agriculture Victoria — Vegetable Growing Guide, NOAA — Atmospheric Lapse Rate and Climate Normals, NIWA New Zealand — Frost Date Records 100% private

Southern Hemisphere seasons are reversed from the Northern Hemisphere: spring runs September–November, summer December–February, autumn March–May, winter June–August. Warm-season crops (tomatoes, peppers, zucchini) are sown September–November; cool-season crops (garlic, peas, spinach, broccoli) in April–July. Garlic is planted April–June for harvest in November–December after 240–270 days.

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: October in Buenos Aires or Melbourne

Month selected: October (mid-spring, soil ~18 °C)
Recommended crops: Tomato, zucchini, pepper, bell pepper, pumpkin

Result: October is the prime transplant window for warm-season crops: tomato seedlings started in August go into the ground now for a January harvest (80-day cycle). Zucchini can be direct-sown for a December crop (55-day cycle). Do NOT sow peas — daytime temps above 25 °C by December will cause pod-set failure.

How it works

4 min read

How It Works

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: ≥ 18 °C (65 °F)
  Cool-season crops: 7–18 °C (45–65 °F)

Reverse Season Rule:
  Southern Hemisphere Month = Northern Hemisphere Month + 6 (mod 12)
  Example: "Plant in April" (Northern) → plant in October (Southern)

Each crop is classified by its minimum soil temperature for germination, its frost tolerance (hardy / half-hardy / tender), and its days to maturity (DTM).

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Monthly Planting Table — Southern Hemisphere

Month	Season	Soil °C	Sow Direct	Start Indoors	Transplant
January	Midsummer	22–28	Beans, cucumber, basil, sweet corn	—	Sweet potato
February	Late summer	20–26	Autumn lettuce, radish, beetroot	Broccoli, cauliflower	Cucumber, pumpkin
March	Early autumn	16–22	Spinach, kale, peas, silverbeet	Cabbage, broccoli	Late tomato
April	Mid-autumn	12–18	Broad beans, garlic, winter lettuce	—	Lettuce, cabbage
May	Late autumn	8–14	Garlic cloves, peas, oats	Onion	Broccoli, kale
June	Early winter	6–10	Garlic, onion sets, fava beans	—	Leeks
July	Midwinter	5–9	Garlic, fava beans, spinach	Tomato, pepper (heated)	Leeks, kale
August	Late winter	8–12	Peas, broad beans, carrot	Tomato, eggplant, pepper	Kale, broccoli
September	Early spring	12–16	Carrot, radish, peas, beetroot	Tomato, capsicum, basil	Lettuce, cabbage
October	Mid-spring	16–20	Zucchini, beans, sweet corn	Pumpkin, corn	Tomato, eggplant
November	Late spring	18–24	Cucumber, pumpkin, watermelon	—	Pepper, zucchini
December	Early summer	22–28	Bush beans, cucumber, basil	—	Sweet potato, okra

DTM reference: Tomato 60–85 days · Zucchini 45–65 days · Broccoli 80–100 days · Peas 55–70 days · Garlic 240–270 days

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Minimum Soil Temperatures for Germination

Crop	Min Soil Temp	Optimal Soil Temp	Best Months (Southern Hemisphere)
Garlic	8 °C	10–18 °C	April–June
Peas	6 °C	10–18 °C	March–May, August
Spinach	4 °C	7–24 °C	March–July, September
Lettuce	5 °C	10–22 °C	Feb–April, August–October
Carrot	7 °C	16–21 °C	March–May, August–September
Tomato	15 °C	21–27 °C	August–September (indoors), Oct–Nov (direct)
Zucchini	18 °C	21–29 °C	October–November
Pepper	18 °C	24–29 °C	August–September (indoors)
Sweet corn	12 °C	21–27 °C	September–November
Cucumber	16 °C	21–29 °C	October–December

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Worked Examples

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: around August 20. Soil reaches 18 °C by mid-October.

Tomatoes: Start indoors early September → transplant mid-October → harvest ~early January ✅

Zucchini: Direct sow October 15 → harvest by ~December 10 ✅

Peas: Too late — temps above 25 °C by December cause pod-set failure ❌

Case 2 — April in Christchurch, NZ (cool temperate, ~43°S)

First autumn frost: typically late May. A gardener wants broad beans (DTM: 85 days) and winter spinach (DTM: 40 days, frost-hardy).

Broad beans: Direct sow April 1–15 → establish before frost, harvest in late July ✅

Spinach: Direct sow April through May — tolerates frosts to −5 °C ✅

Tomatoes: Completely wrong season. Soil already dropping below 15 °C ❌

Case 3 — July in Cape Town (Mediterranean, ~33°S)

Cape Town's mild winters (rarely below 5 °C) allow year-round gardening.

Broccoli 'Waltham 29' (DTM: 90 days): Sow July 1 → harvest early October ✅

Cauliflower (DTM: 80 days): Sow July 15 → harvest early October ✅

Kale (frost-hardy, DTM: 55 days): Sow anytime June–August ✅

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Common Mistakes

1. Using a Northern Hemisphere calendar without offsetting by 6 months. A seed packet saying "sow April–June" means September–November in the Southern Hemisphere. Always apply the +6 month rule.

2. Planting 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.

3. Ignoring altitude. Gardeners in Johannesburg (1,750 m elevation) experience frosts in June–July despite a subtropical latitude. Temperature drops ~0.65 °C per 100 m of elevation.

4. Sowing cool-season crops too late in autumn. Broccoli needs 80–100 days — sown in June in a cold-winter zone (e.g., Dunedin, NZ), it won't mature before repeated hard frosts destroy it.

5. Planting garlic at the wrong time. Garlic requires cold vernalization (below 10 °C for 4–8 weeks) to bulb properly. Plant April–June — not spring — for harvest November–December.

6. Confusing 'sow' with 'transplant' dates. Starting tomatoes indoors in August for a September–October outdoor transplant is correct. Directly sowing tomatoes outdoors in August fails in most temperate zones.

Frequently asked questions

Why is the Southern Hemisphere planting calendar 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. The 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 in the Southern Hemisphere?

Tomatoes require a minimum soil temperature of 15 °C (60 °F) for germination, with optimal range 21–27 °C (70–80 °F). Below 15 °C, germination can take 2–3 weeks or seeds may rot. In temperate Southern Hemisphere zones (Buenos Aires, Melbourne, Cape Town), this means starting tomatoes indoors in August–September and transplanting outdoors in October–November when soil reliably exceeds 18 °C.

When should I plant garlic in the Southern Hemisphere?

Plant garlic cloves in April through June (autumn to early winter) in most temperate Southern Hemisphere zones. Garlic requires cold vernalization — exposure to temperatures below 10 °C for 4–8 weeks — to trigger bulb formation. Without this cold period, garlic grows only as a leaf, producing little or no bulb. From April planting, harvest arrives approximately November–December (240–270 days later) when foliage yellows and falls over.

Can I grow vegetables year-round in tropical parts of the Southern Hemisphere?

Yes. Tropical zones (latitudes 0–15°S, e.g., Darwin, Australia or northern Brazil) have minimal seasonal variation and no frost risk. The main constraint is the wet season (November–April in Darwin), which brings high humidity and disease pressure. The dry season (May–October) is ideal for most vegetables including tomatoes, beans, cucumbers, and capsicum. With irrigation management, warm-season crops can be grown almost year-round.

How does altitude affect the Southern Hemisphere planting calendar?

Altitude reduces temperature by approximately 0.65 °C per 100 meters of elevation (standard atmospheric lapse rate, NOAA). A gardener in Johannesburg (~1,750 m) experiences temperatures roughly 11 °C cooler than sea-level locations at the same latitude, creating frost risk in June–July and a compressed warm-season planting window. Always check local frost date records rather than relying solely on latitude. In South America, Andean zones (Mendoza, Temuco, Quito) can be 3–4 weeks behind coastal calendars.

What is the difference between frost-hardy, half-hardy, and tender crops?

Frost-hardy crops survive repeated frosts (down to −5 °C): 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 or late autumn, or must wait for fully frost-free conditions.

How do I calculate the latest date I can plant before the first autumn frost?

Use this formula: Latest Sow Date = First Autumn Frost Date − Days to Maturity − 14 days (buffer). Example: if your first frost in Christchurch, NZ is May 25, and you want to grow zucchini (DTM: 55 days): May 25 − 55 days − 14 days = approximately March 27. Your last safe direct-sow date is around late March. The 14-day buffer accounts for harvest time and unexpected early cold snaps. Historical NZ frost dates are maintained by NIWA (National Institute of Water and Atmospheric Research).

Which months are best for sowing leafy greens in temperate Southern Hemisphere climates?

Leafy greens (lettuce, spinach, silverbeet) have two main sowing windows in temperate Southern Hemisphere zones (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. Succession sow every 3–4 weeks within the window for a continuous harvest.

Do US or European seed packet instructions 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, climate-specific advice like 'plant after Memorial Day' is regionally irrelevant. Cross-reference with local extension resources: Agriculture Victoria, NZ's Yates Garden Guide, South Africa's Farming Portal, or Argentina's INTA (Instituto Nacional de Tecnología Agropecuaria).

What is the best month to start a vegetable garden from scratch in the Southern Hemisphere?

September or October is the ideal starting point for most temperate Southern Hemisphere locations (Buenos Aires, Melbourne, Auckland, Cape Town). Soil temperatures rise above 15 °C, frost risk is essentially over, and the growing season ahead offers 4–5 frost-free months. Start with easy crops first: lettuce and radishes from seed (ready in 30–45 days), and tomato or zucchini seedlings purchased from a nursery (avoiding the complexity of indoor seed-starting). By January you'll have your first harvests and the confidence to plan a full year's garden.