I'm joining this late, but as I've been a bit of nomad I've lived in most Oz states and grown veg all around the place.
Absolutely the best place for growing veg was at Maleny on the Sunshine Coast in Queensland. Rich, deep black loam, temperatures topping out around 30-32C and rarely dropping below 0, and good rainfall - particularly on the slopes facing west over the ocean. You could stick just about anything in the ground and whoosh, it was away.
The worst place - choose between the far north of Queensland, the far west of NSW or anywhere out along the Nullarbor. The far north because it's both hot and wet (you wouldn't believe the amount of mould and fungus), the far west and the Nullarbour because of poor soil, extreme temperatures (42C and above in the shade in summer, below zero in the winter at night) and no water.
Perth in Western Australia was quite good and Bunbury to the south was even better. The climate is broadly similar to the Mediterranean, the soil was fairly good and rainfall was tolerable.
Canberra was very hot in summer, cold in winter and the rainfall was both unreliable and intermittent. The soil wasn't much good either. Up in the Snowy Mountains at Cooma, the soil was better and the rainfall a bit better but you had serious snow and frosts.
Melbourne was okay, except when the odd duststorm blew in and coated everything in red dust. Soil was dependent on where you lived, but temperatures and rainfall were tolerable to good most of the time.
Port Fairy out on the Great Ocean Road in Victoria was fantastic if you were growing potatoes. The soil was stony but rich, you had good rainfall and the temperatures were mild.
Back up into NSW to the Murray Basin and the alluvial soils were excellent. But, it's been ruined by over-extraction of water so good quality water is a real problem, temperatures are mild to hot. (Relatives worked on an agricultural research station here for years.)
My dad's family is from Lithgow, Hartley and Hampton in NSW, and he still lives there. The soil takes a bit of work but most vegetables grow well if you can get enough water to see them through the hottest part of summer. You do get hard frosts in winter, though, and the odd bit of snow - although there's less and less these days. (We had two cousins die when they were caught out in a snowstorm many years back while trying to bring in cattle, but you don't get snow like that any more.)
Then up to the Hunter Valley (where my mum's family come from). Here, you have excellent alluvial soil along the river, tolerable rainfall most of the time (and drought the rest!) and a good climate. You do get hard frosts in winter, but it's one of the best places in NSW for growing.
My sister (another veg grower) used to live in Tasmania, and said the soils were usually good, with reasonable to good rainfall. Temperatures were a bit on the cool side, but nothing too difficult. She now lives at Oakey in Queensland where it's dry and hot, so most things struggle to make it through mid-summer.
My uncle, who shall remain unnamed, used to live in Darwin and while the plants he grew flourished, they tended to attract the attention of the police!
So there you go, the itinerant vegetable grower's guide to Australia.
Stonehead
PS I'm now working very acidic, very stony soil in NE Scotland, where temperatures hit a high of 21C on just one occasion last summer and plummet to -15C in winter. And don't think we have water - our borehole ran dry in January after a long, dry year; we get barely enough off the roofs for the animals and washing; and we're still bringing in drinking water in jerry cans. (And the English complain about hosepipe bans!)
. Bro in law said - oh, it's just a baby one!!!
