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Making your own bulking agent

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  • Making your own bulking agent

    My Hotbin arrived yesterday and Ive got the first batch underway. Fine!

    My question is about the bulking agent - instructions say "partially composted" wood chip. I have a chipper which can produce a pile of suitably sized chips from woody cuttings - but how long should they be left before they are suitable as a bulking agent? I presume they have to dry out, bur how decomposed must they be?


  • #2
    Hi there,

    You can use fresh wood chips in the HOTBIN as a bulking agent as well as the partially composted wood chips supplied by HOTBIN Composting and they will perform exactly the same function. The best bulking agent is a relatively dry one with a variety of different particle sizes. Please be aware that fresh chippings may take slightly longer to decompose however and may still be visible in the end compost but they will breakdown eventually.

    Should you wish to allow your own wood chippings to become partially decomposed, we would recommend allowing them to season exposed to the elements for a minimum of 16 weeks. After this period you may wish to cover them or move them into storage vessel where they can dry out before being used in the HOTBIN.

    I hope that helps.


    • #3
      Thank you very much, that all makes good sense. BTW my bin reached 70deg in 2 days and is going great!


      • #4
        You are welcome. If you have any other questions, please post them and the HOTBIN community will be more than happy to help answer them for you.

        That's a great start for your HOTBIN. Just keep the HOTBIN fed quite regularly and remember to add some bulking agent and shredded paper each time new material goes in and you should have some good compost in a couple of months!


        • #5
          Thanks this has just answered my question. I have just brought a chipper and have crumbled up branches and twigs stores for the last two months. I added a little today to the HotBin but will find a spot in the garden to start decomposing the rest.


          • #6
            I use non-stained shredded bark on my fruit patch and when it has composted down (takes about a year) I get a few bucketfuls and reserve it for the hot bin. The rest I dig into the soil, as the raspberries and blueberries seems to love it, and then top up with fresh shredded bark. This way I am not buying stuff especially for the hotbin, which really would defeat the object. I don't use shredded junk mail either because of the printing ink on the paper - and I am trying to be as organic as possible. I started out using sawdust, because that is what was advised when the hotbin hit the market, and I still do. I find it doesn't clump provided I also put in the bulkier stuff. I also scavenge my married kids' food waste, and they've each got a bin at their homes which I retrieve on a weekly basis, with strict instructions 'not to let those binmen take my stuff'!


            • #7
              I use sieved compost for sowing seeds and for carrots in pots. The chunky bits left in the sieve go into a bucket for use as bulking agent - they are mainly bits of wood.


              • #8
                Hello! On the subject of making your own bulking agent - I was interested to know whether it is ok to use commercially-bought bags of bark chips. I've got a bag of J Arthur Bower's bark chips which I think I bought from Homebase - the bark pieces are a bit bigger than that contained in the bag of bulking agent supplied by Hotbin, but it looks like it will do the job. It smells very pleasant, quite resinous and rather damp - I don't whether it has been treated and if so, whether that would mean it wasn't suitable for use as a bulking agent. I just wondered if anyone had any thoughts about buying bags of bark/wood chips in this way?


                • #9
                  Hello Robabersoch, you can use commercially bought bags of bark chips as a bulking agent. If the bark chips are rather damp however, you may need to add a little more shredded paper and/or torn cardboard to balance the excess moisture the chippings are adding into the HOTBIN.

                  With regards to the potential for the chips having been treated, we would recommend having a look at the packaging as it should confirm somewhere on the bag whether the chips have been treated and if so, with what and whether it is bio-degradable either immediately or after a certain period of time. Assuming that the chips have not been treated, they will be absolutely fine to add. Please be aware however, that commercially purchased bark chips will likely take longer to break down in the HOTBIN than the bulking agent purchased from HOTBIN Composting as they are not already partially decomposed, so some of the bark chips may still be visible in your end compost. If there are some large pieces left in your harvested compost, these could be removed by hand and added back into the top of the HOTBIN to break down further or could be sieved out depending on the grade of compost you are hoping to achieve.

                  We hope that helps.

                  If you have any other questions, please post them and the community will endeavour to answer them for you.


                  • #10
                    A suggestion for making your own bulking agent. If you grow raspberries, instead of cutting the old canes down after fruiting, leave them standing for a few months, even over winter. They'll dry out to become very woody but, of course, will have a pithy centre. Chopped into lengths of 2 to 4 centimetres they'll make good bulking agent which will also absorb quite a lot of excess water (because of he pith core). They'll also decompose a little quicker than wood.


                    • #11
                      I am thinking of buying a hotbin and wondered if old (couple of years old and dry) fir cones could be used as a bulking agent?


                      • #12
                        I have not bought a hotcomposter yet but am considering a purchase. With regards to bulking agent, I dont feel I would want to be buying wood chip in order to compost it. However I keep chickens and use either a dust extracted chopped straw or a wood based product as bedding. I do prefer the straw bedding and therefore wondered if the used poultry manure and bedding would make an adequate bulking agent. It would certainly make my partner happy not to be taking this to the tip every few weeks and to reuse would be the perfect scenario.


                        • michaelpetersgardenplants
                          michaelpetersgardenplants commented
                          Editing a comment
                          you can buy this sort of wood chip as a pet bedding at a very reasonable price for a large quantity

                      • #13
                        It's there any reason why I can't use small branches from shrubs that I've cut up by hand?


                        • HotBin
                          HotBin commented
                          Editing a comment
                          No reason at all, chop them up as small as you are willing to go, I wouldn't go much thicker than a pencil width or it will just be visible in your final compost, that said however you could process any visible bits through on a second cycle, by chucking them in at the top again!

                      • #14
                        Hi..Can you use sawdust as a bulking agent?


                        • rpwt12
                          rpwt12 commented
                          Editing a comment
                          I don't know about very fine sawdust, but sawdust cat litter works brilliantly for me.

                          I have a lot of kitchen waste and not much garden waste, so I have trouble with wet waterlogged waste turning into sludge that oxygen cannot penetrate.
                          No amount of paper and wood chippings helped: my bin was usually below 40 celcius.

                          Adding our cat's used wood pellet cat litter has solved all this for me.
                          Mixing it in with the kitchen waste and shaking it, you end up with small balls of waste covered in clumped breadcrumbs of sawdust. This appears to be enough to keep air flowing, and it absorbs all the liquid. I now don't bother with paper or wood chippings, so it saves on everything, and my hotbin is always around 70 celcius.

                          I'm not sure why people recommend against this; personally I reckon the hotbin people should be recommending it over artificially adding paper and woodchips.

                          Update: now it's winter that 70 is more like 55-60.
                          Last edited by rpwt12; 02-18-2021, 07:55 AM.

                      • #15
                        Can cardboard be used instead of woodchip as bulking agent?

                        Seems to me that shredded/torn Cardboard might serve as bulking agent. It is able to provide air pockets. Is this correct?