What about plastic pots between the two? Easy enough to remove when you need to replace fence? Planted up with pretty annuals that would spill over? I know nothing about fences but if others say that one will rot they are probably right so you need a short term solution.
Lizzie27's advice is excellent if you intend to do a temporary bodge, but she hints at what lies ahead. This isn't the first post of the type but real fixes are more or less fanciful. If, as Lizzie and others have said, you do the polythene route, suitably drained, you'll then plant something you fancy in the resultant soil. A few years later the fence's uprights will show signs of collapse and, as it's your property, it'll be best to tackle the problem before it falls on someone next door. With so little space at your disposal, all the 'pride and joy' horticulture will be decimated as you dig out the former posts.
Start now with a row of concrete blocks incorporating slotted concrete uprights, and you could insert the existing, or new, panels into the slots as required into the future, thus giving uninterrupted access to the gap in between, but option 3 would be to move the wall a foot or so to the right and eradicate the trouble for good. You have a lot to 'thank' the previous occupant for.
It looks to me as if the land the fence is on is a bit higher than the rest of the garden ... or perhaps the level of the lawn has been lowered? Whichever, that wall has been installed as a retaining wall to shore up the bank that the fence is on ... but it's been built too high ... perhaps because they've used two runs of blocks for cheapness when what was needed was something that could be built more easily to the correct height e.g. bricks, but these would've been more expensive.
I think you need to do a proper job that is going to last and not damage the fence ... one solution would be to take out that block wall and replace it with something of the correct height so that when the gap is filled with soil it doesn't come up to the fence.
An alternative is to follow @nick615 's suggestion but if doing that I would replace the fence now as well. As with so many things ... it probably all depends on how deep your pockets are.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
Posts
Lizzie27's advice is excellent if you intend to do a temporary bodge, but she hints at what lies ahead. This isn't the first post of the type but real fixes are more or less fanciful. If, as Lizzie and others have said, you do the polythene route, suitably drained, you'll then plant something you fancy in the resultant soil. A few years later the fence's uprights will show signs of collapse and, as it's your property, it'll be best to tackle the problem before it falls on someone next door. With so little space at your disposal, all the 'pride and joy' horticulture will be decimated as you dig out the former posts.
Start now with a row of concrete blocks incorporating slotted concrete uprights, and you could insert the existing, or new, panels into the slots as required into the future, thus giving uninterrupted access to the gap in between, but option 3 would be to move the wall a foot or so to the right and eradicate the trouble for good. You have a lot to 'thank' the previous occupant for.
I think you need to do a proper job that is going to last and not damage the fence ... one solution would be to take out that block wall and replace it with something of the correct height so that when the gap is filled with soil it doesn't come up to the fence.
An alternative is to follow @nick615 's suggestion but if doing that I would replace the fence now as well. As with so many things ... it probably all depends on how deep your pockets are.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.