They say ('they' being whoever makes these pronouncements that become folklore) to plant garlic on the shortest day, and harvest on the longest day. But I've been planting garlic in Hobart in April for years, and harvesting in November, and getting beautiful big bulbs! I think that Anzac Day is a good time to think about garlic planting. But this year I'm going to plant a bit earlier - tomorrow!
A good little adage to remember when selecting garlic for planting is: "Plant the best, eat the rest". In other words, break up all your garlic heads into separate cloves, then make two piles: (1) big fat cloves to plant, and (2) skinny little cloves to take to the kitchen for flavouring winter stews. Or whatever your garlic kitchen fantasy.
You can use your own home grown garlic as planting material. Or if you haven't got enough, try the farmers market or good grocers that offer organic Tasmanian garlic. Or barter some from friends. The bigger the cloves you plant, the bigger the bulbs you will harvest. DONT buy imported garlic from the supermarket to plant, because its probably been irradiated (= killed) to make it "safe" for import.
The individual cloves should be planted with the flat part down and the pointy part up, at a depth so that the pointy part is just below the surface. Garlic is tolerant of a wide range of soil conditions, but really likes moderately fertile friable soil (who doesn't) that has been limed maybe 6 months ago.
Watch for weed competition in the first few months, since the skinny little garlic shoots are not competitive at all. If you space the garlic quite close in row (about 10cm between cloves) but at least a good hoe width between rows, you'll make weeding easier.
Yay for garlic, my favorite thing to grow!