What we've learnt to date.....
As you can see it's nothing too complicated. Constructed from thin bamboo and branches from trees in the yard.
(I can't stand to take green waste away from the land. There will always be a pile somewhere for broken branches etc that will either be re-used, decompose or deter termites from the house).
We used 70% UV shade cloth because it gets the afternoon sun. There is a flap that falls down to cover the front.
(All sorts of flowers)
We buy/swap seeds (organic where possible) - it's obviously much cheaper than seedlings and not much more work.
We started by planting straight into the soil (as above). This is fine until you transplant when all the roots are tangled amongst themselves and break.
(Corn, Cucumber & Spring Onion)
We now use individual square holders (as above). Square, as B4C explained, because the roots take better when transplanted (as opposed to round where they tie themselves up). If you still buy eggs, egg cartons seem to work just as well and after a few rounds can be dropped straight in the soil to decompose.
Why not plant straight in the soil?
Too much mulch! Mulch is fantastic and you can almost never have enough - it makes the soil crawl with life, retain water etc etc etc (see "humus")
What soil do you use?
We've started using soil conditioner. Partly because it's the best of a limited range at the hardware store. We tried all sorts of combinations of aerators, additives, soil types... the most important for us was a relatively fine and consistent soil without getting boggy/clay like. (not standard potting mix) I'm sure in time we'll try and do away with buying soil and taking straight from a nice pile of compost....