Decomposing a tree stump
Garden noob
Posts: 260
When we moved into our house there was a tree stump in the garden. It was about 18" high and 12" wide, and would have been an old conifer. I don't know when the tree was cut down, but the stump was fairly solid and I would have guessed it may have been cut ~2 years previously. I wanted to get rid of the stump without much hassle so I decided to start a compost bin over the stump, and hope for the best. Here are my results.
I used a saw to cut a few grooves in the stump and covered the top with soil in the hope of kick-starting the decomposition process. The compost bin was started in March 2014 from scratch and probably took about 6 months to get going (I didn't add any accelerator). It mainly included lawn clippings, leaves in the autumn, and kitchen waste (I'm not fussy about compost). At first it was low on worms so I added some whenever I found them in the garden, and after 12 months it was well stocked.
In July 2015 I removed the compost bin and was pleased to see some signs of decomposition (see the picture on the left). The centre of the stump was starting to decompose nicely. I used an axe to split the stump as much as possible (it would split down to its base) before putting the compost bin back in place.
The picture on the right is from October 2016. I removed the bin and chipped away any soft wood with a spade, which accounted for about half of the remaining stump. The centre 6 inches has completely decomposed to about 6 inches below ground level. The remaining wood feels quite solid but I might use a hand saw on it, or wait 6-12 months for nature to finish the job.
I live in the South East of England but the compost bin is in shade for about a third to half of the day. I'm sure the process could have been quicker if the compost bin were started from a mature compost bin that contained sufficient worms, and if it were turned more regularly.
So, if you're wondering how long it might take to decompose a stump in a compost bin, in my case it's taking about 3 years. 4 years may be a good ballpark for a freshly cut stump.
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Why did you not spend a bit of effort and dig it out?? Cut those exposed roots and heave it out or get someone with a stump-grinder to remove it.
As an aside; worms you find in the garden soil are not the correct worms to put in a compost heap. You want brandlings, tiger or compost worms which will find their own way to compost heaps.
I would turn the question around and ask why go to that hassle of digging it out or the expense of getting it ground up if nature will deal with it for you. The composting method is only an issue if you want a quick solution, or if you don't want a compost bin in that particular spot. I've enjoyed the process of watching the stump decompose and am encouraged that it's been so quick - it's been a nice project.
Thanks for the info about the worms! I always wondered if they were different but never looked it up.
Last edited: 03 October 2016 15:32:15
Go for it! If you're interested, I've subsequently put a sledgehammer to the remaining stump so I now have nothing left at ground level. It's been incredibly straightforward - all you need is a little patience, but not too much. That was a total of 2.5 years for my stump, which I think is quite acceptable.