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Old cattle trough as a planter

Hi all,

So, I've come across an old cattle trough, I'm pretty certain it is galvanised steel, but it is rusting quite significantly (see pic). There is also some patches of white solid encrusting the inner walls which I presume is calcium deposits. It is still strong enough - I've drilled several holes in the base so I've got a feel for its thickness. I intended to plant some edibles in there but I keep having thoughts (dangerous!). From what I can read, rust and Zinc wouldn't be an issue - the amount that will leach into the compost will be comparatively little to the RDA, and the plants will only take up what they need anyway. Do correct me if anyone has an opposing opinion though.

I was thinking of trying to make the interior rust-proof, either by applying a Zinc cold-galvanising spray, or by painting with a rust prevention paint. I've been recommended Hammerite as many of their products can be painted directly onto rust. But I keep wondering whether the chemicals in such products would actually be harmful to both plants and anyone consuming the edibles grown within the trough. If that's the case, I'd prefer to leave out the rust preventative and go naked, so to speak.

I've tried looking up this information online and haven't really got anywhere beyond rust and Zinc are fine. Does anyone have any thoughts?

Cheers in advance.



  • Slow-wormSlow-worm Posts: 1,576
    I don't know about leaching in that instance, and I don't know what's in Hammerite, but you could save a lot of effort and just put a liner in?
  • bcpathomebcpathome Posts: 1,256
    I was going to say that too ……great minds…..
  • Oh yeah, I forgot to say that was a fleeting thought in my mind as well. Forgive me though, I'm new to all this (lived in London until a couple years ago), could you give some suggestions on type of liner, if there are several types?

  • Slow-wormSlow-worm Posts: 1,576
    Have a look at any plant selling/nursery web pages, they'll have all the info on what they sell, and you can see what's available etc. 
  • floraliesfloralies Posts: 2,527
    Empty compost bags are useful as liners or perhaps some pond liner, remember to add some drainage holes on the bottom. As it is metal it will become hot in the summer sun so you need to think about what you are going to grow in it and where to place it.
  • ObelixxObelixx Posts: 29,653
    Any good DIY store or garden centre will have rolls of bubble wrap and plastic sheeting for sale by the metre.   I mention bubble wrap in case you plan on growing edibles through the winter.  A layer of it between the sides of the container and a plastic liner will help insulate roots against excess cold as well as excess heat.

    As has been mentioned, you do need drainage holes in the base to avoid it becoming a stagnant bog.
    Vendée - 20kms from Atlantic coast.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
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