3 months in....

[Garyb]

I got my Hotbin around the middle of December and after some teething problems with getting it kick started, I regularly get 40+ degrees. Tops has been 65 degrees with some periods of cooling to 20 degrees. I find that grass clippings are the catalyst that work time after time. Temps from the internal thermometer.

I am curious as to what temperatures are like deeper down in the bin, though. I'm looking at buying a compost thermometer with a longer stem, but they're quite expensive. If your bin is say, 50 degrees 30cm below the surface at 3/4 full, then what's the temperature likely to be at the bottom?

I find I don't need to add any of the wood chippings at all. I've bought a shredder for the express purpose of feeding the bin and food waste, paper and grass keeps it hot. The obsessive nature of this "hobby", means that I've taken to microwaving the contents of my waste food caddy prior to adding it to the hotbin.......

I will extract my first "harvest" in a few weeks and upload some photos.

[EnlightenedElm]

Hi Garyb,

It sounds as though you are getting some good temperatures in your HOTBIN.

Easy to digest waste types such as fresh grass cuttings and vegetable peelings are quickly broken down by the hot composting bacteria and will usually result in a noticeable increase in your HOTBIN's internal temperature.

Ordinarily, the temperatures at the bottom of the HOTBIN will be between 5-15°C depending on how much material is sitting directly above it. This is because the base layer becomes the least active within the unit as new, fresh waste is added to the top of the unit.

You mention that you have found that you do not need to add any of the wood chippings – can we ask whether you are adding anything similar such as shredded hard prunings? If you are, can we ask what you are using and how often is this material being added into the HOTBIN?

[Garyb]

Hi EE,

I'm not using anything in replacement to the wood chip/bulking agent. I do use a fair bit of paper/shredded cardboard, though.

[EnlightenedElm]

Hi Garyb,

Whilst you are getting good temperatures in your HOTBIN at the moment, it is likely that the temperature will soon drop and refuse to rise despite the addition of easy to digest material such as grass.

The HOTBIN is designed to work aerobically and the addition of a woody material such as bulking agent and/or wood chip is essential to ensure that free air spaces are created throughout the contents of the unit. Without the addition of this material each time fresh waste is added, the waste in the unit will compact and the bacteria will unfortunately become starved of oxygen within a couple of months and the contents of the unit will turn anaerobic. This is characterised by a significant drop in temperature and a putrid odour being emitted.

In order to ensure that the unit remains aerated and balanced, we strongly recommend in the HOTBIN user manual that both a bulking agent and some shredded paper and/or shredded cardboard is added. Please note that both materials need to be added as they perform different roles in the HOTBIN - the bulking agent helps keep the bacteria oxygenated and the unit aerobic whilst the shredded paper and/or cardboard helps to rebalance the internal moisture content and prevents the contents of the HOTBIN from getting too wet.

Going forward, we would advise that you do add some bulking agent or wood chips into your HOTBIN with each new addition of waste to ensure that the HOTBIN can work optimally and does not turn anaerobic. To re-oxygenate the material at the bottom of the unit, you may find it easiest to remove the base layer, mix some bulking agent, shredded paper and fresh waste throughout the material and return it to the top of the unit. This will create the necessary free air spaces whilst the fresh material will provide the bacteria with a new food supply which will help to increase the temperature and to allow the older, partially decomposed waste to breakdown further.

[Garyb]

Thanks EE - I'm due to remove the bottom layer any time now, so I'll see what's been occuring!