Compost thermometer

exwesty, Jan 9, 3:09am
Anyone where to buy a decent compost thermometer in NZ with a reasonable length at a reasonable price?

Best I have seen is the Reotemp from Groundgrocer in Australia so far.

kiwitel, Jan 9, 2:26pm
I am keen for one too so will watch with interest. I got one to use from a course I was doing and it lasted only about 5 times. The button somehow stuck in and I could not get the digital reading after that.

harm_less, Jan 9, 11:41pm
I used to use a glass laboratory/home brew thermometer for my orchard compost heap records. Heaps were in the 100m3 range and I just pushed a shovel handle or pipe into the heap and lowered the thermometer into the hole on a cord.

exwesty, Jan 10, 12:02am
That loses heat but on your scale I don't think it would matter.
What are you adding to your heaps to maintain or increase the temp?

aj.2., Jan 10, 12:22am
AW come on
Whats a thermometer going to set you back in $$$.
Cut some course cuttings for in the bottom of bin , it lets the air in .
Then just cut the grass, spread a bit of lime , cut more grass, etc , And when half full bin , turn it over spread a bit more lime, shovel in a thin layer of soil , then add more cuttings , as you go.
At the full stage give the top section a fork over then Keep the top covered , but do sometimes wet the bin down , after a couple of months it will have sunk down in size , and you fork it over again .
Good compost should be dark and have small bits of wood in it , from tree cuttings etc ,
Add those with the grass cuttings , all helps keep the air flow going and then when you shovel that rich compost out onto garden , those bits of wood , air rates the soil and breaks down even more , feeding those young plants that you have growing .

kiwitel, Jan 10, 12:30pm
Is that answering the question?

harm_less, Jan 10, 2:36pm
Nitrogen rich matter promotes the thermophillic phase which destroys pathogenic organisms amongst other things. Our orchard was certified Organic and we used blood & bone which we had tested for freedom from heavy metals (i.e. cadmium) pre-purchase. Half a tonne of B&B gave us the 55-60 degrees we required.

In a domestic situation chicken manure or fish fertiliser may be preferable to prevent rodent attraction. Our heaps were turned with a hydraulic excavator so any resident rats were likely to add to the nitrogen input.

exwesty, Jan 10, 3:55pm
I put a data logger in the bag last week and just pulled it out of the pile. Top temp of 67 degrees and cooling off now to 55 degrees.

I have used hydrated lime, coffee grounds and a couple of handfuls of blood and bone added to the green waste along with some water.

harm_less, Jan 10, 5:19pm
I assume you're reading 'core' temperature but be aware that unless you are mixing the batch during the heating process the outside zone won't be reaching the desired temp range. Mixing will also limit overheating which 67 degrees is bordering on. If you were to mix now you should see a secondary heating phase as the material from the outer limits is worked on.

Generally the larger the batch, the easier it is to maintain the 55-60 range through turning of the heap. Also if the heap is too large excessive heating can occur which is why commercial composting operations form the compost into windrows.

iluvmuse, Jan 10, 10:27pm
what would be the result of excessive heating?

exwesty, Jan 11, 3:23am
It kills off the beneficial bacteria that are breaking down the waste pile, hence why a compost thermometer to keep an eye on the internal temp in the pile or bag to keep it in the correct zone.

harm_less, Jan 11, 3:24am
Most likely effect is death of beneficial organisms, and less likely combustion. http://www.gardeningknowhow.com/composting/basics/overheated-compost-piles.htm
*snap*

exwesty, Jun 16, 6:20am
I'm going to mix and water the pile tomorrow as it was last mixed on Thursday, it was pretty hot and black in the middle this morning when I dug for the logger. The pile is in a garden bag and is about 1m3