Am I Composting at the Right Temperature (Celsius or Fahrenheit)?

[HotBin]

We often get phone calls from concerned customers "Help my HOTBIN is at 100 degrees, eeek is it going to self-combust."

After a little bit more digging though it nearly always turns out to be 100 degrees Fahrenheit. This is perfectly normal and only just the start of the hot temperatures you are aiming for. Its very easily done and especially seeing as most of HOTBIN's marketing material refers to hot composting temperatures in degrees Celsius.

So to clarify once and for all the hot composting temperatures you are aiming for are:

40 to 60°C (degrees Celsius on the inner ring of the thermometer)

104 to 140°F (degrees Fahrenheit on the outer ring of the thermometer)

Why not share an image of your HOTBIN's thermometer Hot or Cold and tell us how you achieved that temperature?

[Mungusthefogeyman]

Thanks. Clarifies that readings are on the lid thermometer, not in an inserted thermometer. Means I have never made the grade, even in height of summer.

[Christopher Whitmey]

Clarifies that readings are on the lid thermometer, not in an inserted thermometer.

does it? Granted the picture at 24°C looks like a lid one. But posts further down show the critical 40 to 60°C is taken from the inserted one.

[dougal]

Last year I often reached 60deg C., but this year, even in hottish weather and with grass cuttings newly added (usually guaranteed to boost the temp) I have hardly got above 50deg. I have no idea why this is, as I have used the same sort of compost mix.

[Chollerton]

Earlier this year I was reaching 60 degrees, it was after I didscovered that silt had collected at the bottom of the hotbin which had been running for two years and the base had sunk so that it was slightly tipped backwards. We emped it completely - onto an old tarpaulin - removed the base plate and washed it out. The compost which I replaced was very well mixed and the temperature just soared. We went on holiday and while we were away there were terrific rain-storms, when we came back the temperature had dropped considerably and rain had penetrated through the airhole which I had left quite widely open. I'm gradually getting the temperature up but I almost close the air-hole on top when it's going to rain very hard.

[Penellype]

There was one occasion earlier this year when I almost burnt my fingers on the thermometer when I took it out to add more waste. I think I had added some grass in the mix the day before but I am not sure.

[Bullshyre]

I've had my Hotbin now for 2 years and have never reached 40-60 degrees. I have started and restarted the Hotbin numerous times with little or no success. I have also been meticulous with the ratios of bulking agent, paper and waste. I even purchased a P5 security shredder to produce small cross shredded paper. At present my Hotbin struggles to reach 30 degrees and if I'm honest I've been less than satisfied with the results I've had from the Hotbin so I thought I'd join the forum to see if I can finally achieve the advertised temperatures before I throw the towel in.

[ssherlock]

I'm no expert (my bin hovers around 50C quite a bit) but to struggle to even hit 40C you must have an air flow problem. Reading above about how somebody had to empty the bin and clean out the bottom to get air moving again I would suggest doing the same. I'm certainly going to try it as I've often found on emptying that the bottom is either a bit slimy or rock solid (which certainly explains MY airflow issues).
Mine is due its Autumn empty so I'll report back with how cleaning out the bottom properly works for me.
Just for info I have owned my Hotbin since 2012 and blogged about my first years experience at http://blog.sherlock.co.uk/2013/05/h...omposting.html - reason for mentioning the blog post is because it had comments from the Hotbin guys who really helped.

[Bullshyre]

Hi ssherlock, Thanks for the reply.
I have emptied, cleaned and restarted the Hotbin 8 times to date. I have only ever managed to achieve 40C with the regular addition of the water bottle. I would say the ratio, look and content of the Hotbin is the best I've managed so far but again it refuses to go above 25-30C. I'm putting 1 x caddy of food waste, 1 x half caddy of confetti shredded paper and 1/4 caddy of bulking agent in the Hotbin plus 1 x caddy of grass with the same ratio of paper and bulking agent once a week. The base and vent at the bottom are definitely free from debris. I purchased the Hotbin thinking it would be an easy way to compost but it has provided nothing but frustration so far. I have also played around with the valve settings with no success. I have never had the temperature of the Hotbin soar to 60C even with grass, no matter how much is added, it's very frustrating.

[Penellype]

How full is your bin Bullshyre? I find you need it to be at least 1/2 and preferably 3/4 full before the temperature will rise to 40C.

[Bullshyre]

Hi Penellype, my Hotbin is currently 3/4 full. I have had a concentrated effort on the Hotbin today whilst doing the garden. I have emptied 3 caddy's of waste and grass into the Hotbin using the ratios in my earlier post. The temp is currently a little over 30C, hopefully the temperature will increase but I won't hold my breath

[PRS]

Hello Bullshyre, I have also struggled to get the Hotbin to 40 degrees and have tried various recommended strategies unsuccessfully.Recently I decided to 'feed' the bin every other day (with the recommended ratios etc) and I have found that the temperature moved up to 40 degrees. I then ran out of old/decomposing woodchip and changed to new chips (which were free) and this seemed to reduce the temperature but its creeping up to 40 again. I do not want to spend money on buying the bulk material, so will persevere with these new chips if they work.
I've found it very disheartening not getting higher temperatures but its good (for me) to hear I'm not alone - lets hope we have more luck soon!

[WiseOldBloak]

When you are taking a temperature reading are you using long stem internal thermometer or the lid thermometer? I now only use the lid thermometer as a gauge to see if the temperature has increased or dropped as I have found there can be up to a 20 to 30°C variance in the two thermometers. I normally find that if the lid reads 25°C then the internal temperature can be anywhere between 40 and 55°C (especially if the bin is only half full or less).

[Penellype]

I use the internal thermometer. The one in the lid is really only a guide and I find it generally about 10-15C below the internal one, unless it is in the sun.

[Bullshyre]

Hi PRS, Thanks for the info. I somehow think we won't be the only ones struggling to reach a decent temperature.

[Bullshyre]

I always use the internal thermometer and use the lid thermometer as a guide. I only see a 10C difference nothing more but then again I am yet to achieve a steady 40C-60C despite my best efforts over the 2 years.

[davidmwoods]

My Hotbin is in s sunny position that helps to maintain a good temperature. I suggest that you restart the bin with a plastic hot water container buried in the fresh added material. Leave for 24 hours. Add small qauntities of green plants every day and sometimes add some water if the compost is too dry. I am achieving 60 - 100 degrees most of te time.