Raised vegetable gardens

Can anyone give me some advice! I have had 2raised vegetable gardens for about 4 years now which we built when we moved into this property.They have supplied us well with winter and summer vegetables.This year my gardens have not done so well and I now realise the roots of the neighbouring tree near my gardens are all in my soil.At the beginning of summer I spent many hours getting rid of these roots and now they are all back again.We put macrokapa (sp) on the garden floors when we first built the gardens but nothing else. I am thinking we may have to dig up the gardens taking all the soil off and lay something down that will keep the roots away then start again.I look forward to any opinions or advice.Thanks

We have a stand of redwoods some 10 metres from the edge of our garden and have found the only answer is either at least annual deep cultivation and plenty of fertiliser to feed both veges and tree roots or else (or as well) laying some impermeable material such as heavy black polyethelene at least 200mm below the bed to prevent root incursion. To allow drainage use overlapping small sheets rather than a contiguous layer.

Well, I do know of someone with raised gardens who lined them all with plastic to keep away the weeds.Alas the result was that after a bout of rain he went up to his knees in mud when he stood on the garden!
So I would guess if you get something strong enough to keep the tree roots out, you're also going to be keeping the water from draining away.

Imo you need to put a barrier between the roots and the bed, digging a deep ditch down the side of the garden and either filling it with concrete or a barrier of corrugated iron. If you line the beds with an impermeable membrane, the soil can't drain and the plants will die.

I doubt that's an issue, we've had gardens with tree roots encroaching, never affected the produce. More likely the drought this year.

Thanks for your suggestions.Its not the drought as when I dig over the soil it is hard work as these roots have formed even though they are not huge they still clog up my soil.If I laid sacking material then applied the soil would this help keep the roots down!Deep cultivation with a cultivating machine might be the answer to save alot of hard hand digging.