The floppy fence is designed to primarily keep possums, wallabies and rabbits (and other undesirables) out of your food garden.
The material list is fairly straightforward and includes chicken wire (rolls at either 1.8m high or two rolls at .9m high), star pickets (at least 1.8m high), tie wire, high tensile wire and vermin mesh or small chicken wire (optional).
Avoid using timber posts as possums climb them more easily than steel posts, and if you have particularly vigorous possums you might want to consider eliminating all timber from your fenceline.
Cost will vary depending on the area fenced - fencing isn't cheap and it can quickly add up. However you can salvage a lot of the materials or find them second hand which helps keep the costs down. Just remember that long-term, it's worth the investment in time and finances for a safe and productive food garden.
How do we keep out rabbits, wallabies AND possums?
Well there are a few key elements which specifically target each species...
At the bottom of your fence dig in an additional 20-30cm of chicken wire straight down into the soil, creating a barrier to rabbits digging under/through the fence.
Alternatively you can put a 20-30cm 'skirt' on the bottom of your fence where, instead of being dug into the ground the wire is fanned out along the soil's surface. Remember BABY rabbits can squeeze through extra small fencing wire.
You'll see on the diagram that additional wire has been added to the bottom strip of the fence to deter these babies and you can use either vermin mesh or small chicken wire to keep them out.
The element preventing possums rampaging in your garden is the top floppy section. Possums hate climbing on unstable, shaky branches so we're imitating this with the floppy top.
They'll climb the fence as normal, but once they reach the top floppy section they'll turn around and retreat.
The wonderful thing about wallabies is they don't jump very high so all you need is a standard fence up to approximately 1.5m high with no floppy top or skirt required.
There are many variations of the floppy fence depending on the materials available and the context in which they're working. For example Pindari Herb Farm has incorporated corrugated iron into their fence structure to act as a wind/seed break.
I've also seen this used to keep out wombats, but you have to dig the iron into the soil a good .5m as well.
One very important factor is that the height of a floppy fence will vary drastically depending on the vigour of your possums/wildlife.
For example we live in urban/peri-urban Hobart and our floppy fence is around 1.5m high, however we know people living in the country who build theirs well over two metres high with an electrical wire on top of that to keep out the possums.
Have no illusion about possums - there are some determined ones out there who will stop at nothing to get to your crops.
The main thing to remember is that fencing is your friend so get over any 'oh, but fences create a bad vibe' feelings. Do what you need to do to make sure you can grow food without a constant battle with the wildlife.
I've seen too many half-hearted attempts at fencing which have resulted in huge amounts of energy, time and resources wasted and ultimately people decided that growing food was 'too hard'.
Generally it's not too hard, you just need the right fencing design for your situation and get into it.