Autumn Sowing in Australia: What to Sow in March, April and May

The short version: Autumn sowing is about size, not survival. You are sowing so a plant reaches a usable size before growth slows for winter, which is why the early end of each window matters far more in autumn than it does in spring. March is the widest sowing month across most of the country, April is the steady one, and May belongs to broad beans, garlic and the mild-winter zones. Work from your own first frost date rather than a national calendar.

Autumn is the quiet opposite of spring. In spring you are waiting for the soil to warm, and a fortnight of patience costs almost nothing, because conditions improve behind you. In autumn the season is walking away, and a fortnight of delay is a fortnight you do not get back.

Autumn sowing is about size, not survival

Winter does not usually kill a well-chosen cool-season crop. It stops the crop getting any bigger, so whatever size a plant reaches by late autumn is roughly the size it holds until the days lengthen again. The job of an autumn sowing is to bank that growth while the soil is still warm.

Garlic makes the point plainly. The New South Wales Department of Primary Industries factsheet on growing garlic in NSW explains that autumn planting gives a long leaf-building phase, that bulbing then starts in response to higher temperatures and lengthening days, and that leaf growth stops once bulbing begins. Its general rule is that the longer the vegetative period, the larger the bulbs. You do not control the switch. You control how much growing the plant has done before it flips.

Research points the same way. In the Grains Research and Development Corporation faba bean planting guide for southern Australia, faba bean and broad bean respond markedly to time of sowing, with an average of about 250 kg per hectare lost for each week of delay. That is a broadacre figure rather than a home bed, but the mechanism is the one in your garden: a plant that starts late finishes small. So if the choice is a slow crop sown this weekend or a better-prepared bed in three weeks, sow this weekend.

Find your own dates instead of trusting a national calendar

The date that matters is your own first frost, and it is stubbornly local. Two gardens in one suburb can differ noticeably. Here is how to look it up in about five minutes.

1. Open the frost maps. The Bureau of Meteorology publishes annual and monthly potential frost days, drawn from 1976 to 2005 data at about 1,300 stations. Choose the "less than 2 degrees" threshold, then step through March, April, May and June and watch when the colour reaches your district.
2. Use 2 degrees, not zero. Bureau thermometers sit about 1.2 m above the ground, and its explainer on frost notes that a screen reading of 2.2°C indicates the surface temperature is approaching 0°C. A forecast minimum of 2 degrees is a frost night at seedling height.
3. Check your own station. In Climate Data Online, choose monthly temperature statistics and type your town. At Canberra Airport the mean minimum falls from 11.3°C in March to 6.8°C in April and 2.5°C in May, which is a more honest picture of the season than the word "autumn".
4. Count backwards. Cauliflower, Brussels sprouts, leek and parsnip want to be well up and growing a couple of months before that first frost. Fast leafy crops can go in much closer to it.

The six zones below are broad groupings rather than lines on a map. If you garden between two of them, in a frost pocket, a coastal strip, or a valley that behaves nothing like the town twenty minutes away, lean on your own first and last frost dates and treat the months as a guide.

Zone	Peak sowing window	Get this in first
Tropical	April to July, with March for seedlings under cover	The cool-season crops the wet will not carry
Subtropical	March to June, with cauliflower in by April and Brussels sprouts by May	Brassicas and root crops in March
Arid and semi-arid	March and April	Brassicas, roots and onion, before the nights drop
Temperate	March and April	Cauliflower, Brussels sprouts, leek and parsnip
Mediterranean	March to May, opening with the rain	Whatever you can water until the break arrives
Cool and alpine	Late summer to early April	Everything slow, and it is already late

March: the month that decides the winter patch

March carries the widest sowing list of the autumn almost everywhere south of the tropics, because the soil is still warm from summer while the air has stopped punishing seedlings.

• Tropical (Darwin, Katherine and the Top End of the Northern Territory, Cairns and Townsville in north Queensland, and the Kimberley in Western Australia). The wet is still running, so March is for raising seedlings in trays under cover rather than sowing beds. The Northern Territory sowing calendar for Darwin and Katherine opens in March only for beetroot and shallots, apart from the few crops it carries all year, and cabbage, cauliflower, broccoli, the Chinese greens, silverbeet, spinach, lettuce, baby carrot and radish all open in April. Darwin Airport averages about 311 mm of rain in March, so start the April crops in trays now and plant them out once the ground drains.
• Subtropical (south east Queensland from Brisbane and the Gold and Sunshine coasts to Bundaberg, and northern New South Wales from Lismore to Coffs Harbour). The overlap month, and the one place you can sow both halves of the seed tin. Queensland horticulturist Annette McFarlane still lists cucumber, sweet corn, capsicum and French beans for subtropical March alongside the cool-season crops. Direct sow carrot, beetroot, radish, rocket, silverbeet and spring onion, and raise brassicas, lettuce and leek in trays out of the humidity.
• Arid and semi-arid (Alice Springs and Tennant Creek in the Northern Territory, Broken Hill in New South Wales, Mildura in north west Victoria, Port Augusta in South Australia, Kalgoorlie in Western Australia, and the dry inland of Queensland). The big month. The Northern Territory calendar for the Alice Springs region carries beetroot, broccoli, cabbage, carrot, cauliflower, lettuce, onion, radish, silverbeet, spinach, swede and turnip through March, marking the root crops for direct sowing and the brassicas for seedlings. Nights at Alice Springs Airport average 17.7°C in March and 8.1°C by May, so growth you get now is growth you get cheaply.
• Temperate (Sydney, Newcastle, Wollongong, Melbourne, Geelong and the coastal districts of New South Wales and Victoria). The widest list of the autumn. Gardening Australia lists beetroot, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, kale, kohlrabi, leeks, onion, parsnip and swede for temperate March. Direct sow the roots and leafy crops, raise the brassicas and leek, and start garlic cloves. Cauliflower and Brussels sprouts are the slowest of them, so they go in first.
• Mediterranean (Perth and the south west of Western Australia, Adelaide and the gulf and coastal districts of South Australia). The crop list matches temperate, but the water does not. Green Adelaide lists beetroot, broccoli, Brussels sprouts, carrot, cauliflower, kale, parsnip, silverbeet, spinach and garlic for March, while Perth Metro averages 20 mm of rain in March against 86 mm in May. Direct sow the roots, raise the brassicas, and treat March sowing here as a decision about your hose.
• Cool and alpine (Hobart and most of Tasmania, Canberra and the Australian Capital Territory, Ballarat and the Victorian high country, Orange, Bathurst, Armidale and Katoomba in the New South Wales tablelands, and the Adelaide Hills in South Australia). The last full month, and it tightens as it goes. Peter Cundall, in his year-round Tasmanian planting guide, sets beetroot, carrot and parsnip for early March, then turnip, English spinach, broad beans, Asian vegetables and a cover crop. Brassicas do better going in as seedlings than as seed from here on.

April: the steady month

April is when the legumes open across most of the country and the north hits its stride. It is also the last comfortable month for anything slow in the colder half of Australia.

• Tropical. The best all-round sowing month of the year. Rain at Darwin Airport drops to about 102 mm, direct sowing gets easier, and the Northern Territory calendar opens for cabbage, cauliflower, broccoli, silverbeet, spinach, lettuce, baby carrot and radish alongside capsicum, chilli, eggplant, garlic, cucumber, zucchini, okra, cherry tomato and the Chinese greens. Full-sized tomato and spring onion wait until May.
• Subtropical. Peas and snow peas open and the brassica list is at its widest. Gardening Australia lists broad beans, broccoli, Brussels sprouts, cauliflower, celery, garlic, kohlrabi, onion and peas for April here. Direct sow the peas, roots and leafy crops, and raise the slower brassicas and celery.
• Arid and semi-arid. The last easy month. Broad beans, peas, parsnip and bok choy join the Alice Springs list, all sown direct, and onion is still going in. Nights are falling quickly and inland frost becomes a real limit from May, so favour beds you can throw a cover over.
• Temperate. The legume month. Broad beans, peas and snow peas go in direct, and garlic and onion follow. Broccoli, cabbage and cauliflower can still be sown into trays, though late April is the honest edge for cauliflower in a cold suburb.
• Mediterranean. Often the month the autumn break arrives, the first soaking rain of the growing season, though in Perth it is as likely to be May, because April averages 35 mm of rain against 86 mm in May. Broad beans, peas, broccoli, cauliflower, kale, spinach, swede, celery and garlic all suit April, with the legumes and roots direct and the brassicas raised. If the rain has not come by late April, water the bed thoroughly the day before you sow rather than sowing into dust.
• Cool and alpine. The sowing list narrows sharply, to broad beans, spring and salad onions, English spinach, Japanese turnip, and Asian brassicas and root crops. Nearly everything else is better planted as a seedling. Mean overnight temperatures at Canberra Airport are down to 6.8°C.

May: the tail, and the start of next year

May is two different months depending on where you stand. In the north and the Mediterranean zone it is prime sowing time. In the temperate and cool zones it is the tail of the window, good for legumes and fast greens and not much else.

• Tropical. The dry season proper, with rain at Darwin Airport averaging 20 mm. Cabbage, cauliflower, broccoli, capsicum, chilli, garlic, cucumber, silverbeet, carrot and radish all still sow, full-sized tomato and spring onion open this month, and direct sowing is straightforward now the ground has dried. The catch is that you now water everything you plant.
• Subtropical. Last call for the slow brassicas, which are better put in as seedlings now, and prime time for broad beans, peas, garlic, onion, parsnip and the leafy crops sown direct.
• Arid and semi-arid. Last call for the brassicas, which finish on the Alice Springs calendar between April and June. Broad beans, peas, onion, spinach, silverbeet, radish and the root crops all still appear for May, sown direct, and most of them run on through June and July. Frost is now the limit inland rather than heat, so sow where you can cover the row.
• Temperate. The list is shorter, and the gaps are the lesson. Gardening Australia lists broad beans, cabbage, carrots, garlic, kohlrabi, lettuce, peas, radish, rocket, silverbeet, spinach and turnip for temperate May, with broccoli, cauliflower, Brussels sprouts, leek and beetroot dropping out after April, and parsnip after March. Onion is the useful exception: the New South Wales onion growing Agfact records most commercial sowing in the state from early to late May, because onions bulb on day length rather than on the calendar.
• Mediterranean. May is not late here. Perth Metro averages 86 mm of rain in May and 127 mm in June, and Green Adelaide still lists broad beans, broccoli, cauliflower, kale, peas, spinach, swede and garlic. If your break came late, May is your March.
• Cool and alpine. Sow broad beans, English spinach, Asian brassicas and root crops, spring and salad onions and a cover crop, and plant the rest. The mean May minimum at Canberra Airport is 2.5°C, which by the Bureau measure is a night sitting at the frost threshold. Anything sown now germinates slowly and then waits for spring.

What not to sow in autumn

Every April, someone in Melbourne sows tomatoes. It is an easy mistake, because the weather is still pleasant and the packet says nothing about latitude. Outside the tropics and subtropics, leave these for spring.

• Warm-season fruiting crops. Tomato, capsicum, chilli and eggplant need a long warm run to ripen fruit, which is why they are absent from the temperate and cool autumn lists rather than merely overlooked.
• Cucurbits, beans and sweetcorn. Cucumber, zucchini, squash, pumpkin, melons, beans and sweetcorn all want warm soil to germinate and a warm run afterwards. Broad beans are a different plant, Vicia faba rather than Phaseolus vulgaris, and they belong in autumn.
• Basil and the tender herbs. Sow coriander, parsley, chervil and dill instead, which prefer the cooler half of the year.
• Slow brassicas, late, in a cold garden. Cauliflower and Brussels sprouts sown from seed in May in a cool or alpine garden will generally sit rather than head. Plant them as seedlings in March, or shift the plan to a spring crop.

In the tropics the list runs the other way. The crops to avoid there are the long, leafy ones that would still be standing when the wet returns.

The crops that go in now or wait a year

• Garlic (Allium sativum). Planted as cloves rather than seed, from about March to May across most of the country. NSW Department of Primary Industries names autumn, March and April, as the main planting time in that state, with maturity from early November to January. Miss it and the next chance is twelve months away.
• Broad beans. Sown from March through to about June depending on zone. Growers in Victoria are advised to sow faba bean from mid April to the first week of May, and on acid soils in southern New South Wales from 20 April to 15 May, because crops sown later flower into rising spring temperatures. A home bed is more forgiving than a paddock, but the direction of the advice holds.
• Onion from seed. A long crop that builds leaves through the short days and bulbs as the days lengthen. Sow in autumn or accept a smaller bulb, because the New South Wales Agfact notes that July and August plantings leave less time before bulbing starts. Match the variety to your sowing date as well, because the same Agfact warns that sowing a storage variety such as Creamgold too early can cause bolting.
• Leek, parsnip and Brussels sprouts. Slow enough that a late autumn sowing rarely repays the space, so put them in at the front of your window.

A bed with nothing to grow in it

If a bed empties in autumn and nothing on the list suits it, sow a cover crop rather than leave bare soil to take the winter rain. A legume such as field peas, faba beans or woolly pod vetch paired with a cereal such as oats or cereal rye gives you nitrogen and bulk from one sowing, and you cut or turn it in before it sets seed. Our guide to winter cover crops by climate zone sets out what suits each region, and the cover crop and soil builder range covers the autumn and winter options. Due to quarantine restrictions and our shipping policy, the ready-made autumn and winter blend cannot be sent to Western Australia or Tasmania, so gardeners there should choose a single-species cover crop that ships to their state.

If you are already late

Being late in autumn is common and not fatal. It changes what you sow rather than whether you sow.

• Switch to fast crops. Radish, rocket, mustard greens, mizuna, bok choy and baby-leaf lettuce and spinach give a picking in weeks rather than months. Sow a short row every two or three weeks, and allow longer than the packet says once the days shorten.
• Buy seedlings instead of sowing seed. A punnet of brassica seedlings buys back four to six weeks, which is roughly what a late sowing has lost. It is the most useful fallback in a cool or alpine garden from April onwards.
• Sow under cover. A cold frame, a hoop tunnel or a tray on a sheltered verandah lifts the temperature enough to get germination away. Our guide to preparing the garden for winter growing covers the protection options and how long each crop really takes once the days are short.
• Change the target. A late broad bean or pea sowing still crops, just later. A May sowing in a cold garden is often best understood as an early spring crop that happens to be in the ground already.

Frequently asked questions

When does autumn sowing start in Australia?

In cool and alpine gardens it starts in late summer, often February, because the season closes early. In temperate, Mediterranean and arid gardens March is the opening month. In the subtropics it begins in March as the heat eases. In the tropics the Northern Territory calendar opens in April once the wet ends, with March for raising seedlings under cover, and both zones run later than the south.

Is April too late to sow broccoli and cauliflower?

It depends on your zone. In subtropical, Mediterranean and mild temperate gardens April is a normal month for both. In cool and alpine gardens and cold inland pockets, an April sowing of cauliflower usually runs out of season, so seedlings are the better bet.

What about Perth and southern Western Australia?

The Mediterranean zone works to rain rather than to a date. Perth averages 20 mm of rain in March and 86 mm in May, so an early sowing needs watering while a later one rides the autumn break. Sowing at the front of each window still pays, provided you keep the seedbed damp.

One planning step before you sow

Find your first frost month on the Bureau of Meteorology frost maps and write it somewhere you will see it, on the seed tin lid or the back of the shed door. Then work backwards: garlic, leeks, parsnips and the slow brassicas first, legumes next, and fast greens for as long as the weather allows. Our Australian sowing almanac gives the month-by-month picture for the rest of the year, and our guide to cool-season vegetables across Australia goes crop by crop once the sowing is done. When you are ready to choose, the autumn and winter seed range is where the season starts.