What to do with soil that's got coal in it

Hi - just recently had the patio removed and discovered underneath it are wall foundations of an old building, which I think might have been a coal shed at some point because my beautiful soil has lots of tiny bits of coal and coal dust in it. I was intending to grow flowers, fruit tree, raspberries and/or runner beans because it's a lovely sunny spot and my normal soil is fabulous but not sure if it's now contaminated. What shall I do? If I dig it all out and replace with new top soil, to what depth should I dig? Any ideas, anyone? Also, if i have to buy new top soil, are there different sorts and which one should I get. Many thanks.



  • WelshonionWelshonion Posts: 3,115

    Coal is not really contamination; it came out of the earth, it is just charcoal in another form.  Add plenty of compost/humus to the soil, and off you go!

  • I would suggest either digging it out and replacing it with clean top soil or putting a raised bed. Even though you don't mention that there is coal cinders there, it is always a possibility. Coal contain many toxic elements and heavy metals, therefore to place fruit trees that are going to absorb these elements and find their way into your diet is a bad thing.

    I'm no gardener, having only been on this site for 2 days, but I am studying for a science degree in geology, so know a little about the possible contaminations that can occur.

    HTH's. I would be interested to see what a gardeners perspective is on this matter.
  • ha my first two responses have totally opposite views! (but thank you for being so quick)

    wonder what anyone else has to say?! 

    havent seen any cinders yet. just looks like black coal bits but also have found some pinky orange clay, which is weird because my soil type is river basin valley stuff, ie very dark and no clay at all. 


  • My Grandad's garden was heavy clay (so much so I took some into school and my pottery teacher fired it as an experiment), and that had tiny bits of coal in it.  Have you tried digging down to find out how deep it goes?  Obviously if it's only a couple of inches, then I'd move it, but if the clay goes down more than a foot, it will be one helluva job to shift it.

    Personally, I'd see how far down it goes before deciding on anything.  If you get fruit trees, you can keep them in pots for a few years, so if there's lots of contamination, shift it in stages, but still have your fruit trees, and hopefully by the time they need planting in deep soil, you'll have fixed your problem.

    My Grandad planted some fruit & veg in his garden (after adding LOTS of sand and manure), and was in his 70's when he died, so if there are tiny bits of coal in a heavy clay soil, then I can't see it being a problem, as it didn't affect him (mind you the smoking and drinking he did didn't seem to affect him, and I wouldn't advise doing either)!  I don't claim to be a scientist, but I think most of the nasty stuff in coal is released when the coal is burnt (heavy metals and sulphur), so if it's not burnt I don't think you'd have a problem.

  • hi MMP - i'm waiting till the builders have gone, then I'll do as you say and dig deep just to really see what's what. thanks for advice.

  • Ignore my original post for the time being. I was a bit hasty in my response, and as there is conflicting opinions, I feel I should do a bit of research in the matter for you before I comment further. As I said, training as a geologist, not an environmental scientist or biologist, so will have to look into it before I am confident in backing my original post. image
  • yvonne1yvonne1 Posts: 6

    As an older gardener and mother of 4 I'd just like to point out that many pregnant women eat coal and many children also.  To my certain knowledge no one has yet died, been poisoned or suffered internal problems.  Dig the soil out if you want, or leave it and as already advised add plenty of organic matter and plant what ever you choose.  Happy gardening

  • After doing a bit of digging (no pun intended), it is probably ok to plant on the space if it is just coal/dust. But as said before, if there is any sign of coal ash, probably not a good idea. Although US environmental studies shows that small amounts of ash are beneficial to crops with little uptake of contaminants. But this depends on the crop planted, leafy plants, such as lettuce and spinach, show high concentrations of contaminants within their structure, whilst more fleshy plants like peas, beans and FRUITS tend to show small uptake but with high concentrations on the fruits surface that can be easily washed off.

    Quite interesting reading about this, and may be a possible research proposal as there is not much research on the implications of small scale contamination and the uptake of contaminants by the biosphere. Most research is done on the large scale contamination caused from power plants etc.
  • BerghillBerghill Posts: 2,826

    Every inch of our garden contains bits of coal and in places it is almost pure cinders. The Veg gardens have the least coal and no cinders, and we have had no problems so fat in 20 years of eating.

    Be glad your garden does not have our major contaminants.......hundreds of batteries from the old accumulator types with lead plates to modern torch batteries. We had to put the Veg  areas where there was the least number of these things.

    I think the clay residue is possibly from the coal fires.

  • wow! what a brilliant lot you are!  i really appreciate all the helpful advice. 

    richardsdrr - I'm impressed with all your research and look forward to hearing anything exciting 

    berghill - I'm sorry about your batteries 

    yvonne1 - yum!  I'll get stuck in, then!

Sign In or Register to comment.