easy, buy a kilo of carrots about $1.00 kg at Aldi...place one...

easy, buy a kilo of carrots about $1.00 kg at Aldi...place one carrot chopped lengthwise on a small shelf on top of your fence...at roughly 10 carrots per kg it costs 10 cents a day...possum loves carrots, apple, peanut butter sandwiches...and will not bother with your garden

I alternate an apple or carrot a day for my possum family

it has worked for me...they ate $50 worth of new parsley in pots, the first night after I purchased the parsley
they do not touch any other plants
although there is a small strawberry patch, that is for them only (I dont like strawberries)

lately I have fed them celery sticks, and anzac biscuits, weetbix, or any other healthy left over food

You are not allowed to trap them, and wildlife officers can only remove them to 50 metres away....as if they are not going to walk 50 metres home

alternatively, if you have a spotted quoll in your patch, they eat possums
I find the feeding method works the best, then you both live happily ever after....