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Raised bed lined with plastic

I am new to the forum and relatively new to gardening. 

A couple of years ago, with new found enthusiasm, I started my venture into growing vegetables. I built a 2ft high, large raised bed. 

To protect the wood from rot, I lined the raised bed in plastic. Unfortunately, the exposed plastic has began to break down in to small fragments which are now in the raised bed. I have now removed all the exposed plastic to prevent further breaking down, however, undoubtedly, there will be a lot of fragments still left in for the next growing season. 

My question is, will the small fragments eventually make their way into the vegetables and what would be the best way to remove the fragments in the soil.  And finally, what is best to line the raised beds in future? 

Thanks very much for your time.


  • FairygirlFairygirl west central ScotlandPosts: 49,086
    edited 15 January
    I've always used plastic to line my raised beds @james.gutridge and I've been doing that for a long time, in several gardens,  without any problems. 
    It might be down to the type pf plastic you've used. It certainly shouldn't break down in only a couple of years.  :)
    Do you have any photos?

    I doubt they'd get into the veg, but as I've never experienced it, I'm not sure.
    I've just realised you said exposed plastic. Why is it exposed?
    It's a place where beautiful isn't enough of a word....

  • JennyJJennyJ DoncasterPosts: 7,690
    I expect the soil has settled a bit and the level dropped, leaving the plastic showing at the top. Some plastics do break down in light, or generally over time (I had some bags with stuff in, in my loft (dark) and after some years they just crumbled into bits). Bags that compost and suchlike comes in was always a good bet for lining raised beds, bog gardens etc but maybe they're making it so that it degrades these days.
  • Hey guys. 

    Thanks for replying.

    I suspect its the type of plastic used but I can't remember what it was when I bought it.

    The soil has settled and left the top few inches exposed and think the weather may have caused to to go brittle and disintegrate (See attached photo). Best case it biodegradable, I just hope it won't find its way into the food somehow? 
  • philippasmith2philippasmith2 Posts: 2,424
    As per @Fairygirl, I have always used old soil/compost bags to line my raised beds and haven't had any problems with them breaking up. I haven't noticed any difference in those from last year as to those from 4 or 5 years ago.
    Some plastics will deteriorate when exposed to sunlight and keeping your beds topped up may help to a degree.
    Certainly not ideal but I don't think the bits of plastic will affect your veg.  The only way to fully clean your beds is to empty them and pick out the plastic - a long tedious job - and then re line your beds ( compost bags as described or perhaps Butyl or similar pond liner material ) and start again.
  • FairygirlFairygirl west central ScotlandPosts: 49,086
    Yes - it doesn't really look fit for purpose, that plastic.
    I had a roll of heavy duty plastic which I brought from a previous property, but pond liner is brilliant, and you can get it fairly cheaply from various online suppliers. Bradshaws etc. 
    Raised beds will always need topped up - usually every year. It can also help if you put an edging round the top of your beds. It makes them look better, and hides the top of the plastic.  :)
    It's a place where beautiful isn't enough of a word....

  • philippasmith2philippasmith2 Posts: 2,424
    Pic wasn't showing when I posted but agree with @Fairygirl - that plastic isn't suitable for your purpose.
    The trouble with raised beds is that you do need to keep them regularly topped up whatever you use to line them with.

  • Thanks again for your comments. 

    I agree, in hindsight, its not a very durable plastic. I wrongly assumed all plastic was the same. 

    To save a lot of time, I might pull back the soil into the middle of the beds, assess the situation below the soil line and re-line above the soil layer with durable pond liner then top up with good quality compost? 

    I'm hoping this is the quickest, cheapest and healthiest option? Unless anyone would suggest otherwise? 

  • FairygirlFairygirl west central ScotlandPosts: 49,086
    Don't just use compost for topping up though. Use either a soil based compost, or actual soil mixed with compost or leaf mould or similar. That will help to prevent the bed drying out too quickly, which is the advantage and also the disadvantage of raised beds  :)
    Depending on what you're growing, you can add grit for extra drainage, or use more soil if it's for plants which need more moisture. Your climate, is also a factor - in hotter, drier areas you'll need extra heft to the soil mix, and in very wet areas, you'll need more drainage  :)  
    If your beds are part of an ornamental space, it's worth adding a little finishing 'edge' round the top of the beds. It helps to hide the top of the plastic , and looks better. Mine are all edged. 
    It's a place where beautiful isn't enough of a word....

  • Fantastic, thanks for the great advice. 

    Yes, it was always my intention to add a finishing edge. Perhaps this will give me the push I needed to get it finished and tidied up. A little winter project to keep me occupied. 

    Thanks again. 
  • FairygirlFairygirl west central ScotlandPosts: 49,086
    It [the edging] makes all the difference @james.gutridge  :)
    Mine are largely for ornamentals, although I stick the odd bit of lettuce etc in among the planting if there's room. I can also sit on mine, if I feel inclined, as the edging is wide enough, although many of the plants spill over, so I rarely do it. 
    An old photo from the year after I moved in and did them- but you get the idea. Mine are all odd shapes too because of the boundary and the general layout

    It's a place where beautiful isn't enough of a word....

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