I use a steel rod about 3ft long. If I can hold it indefinitely, it is less than app. 150 Deg F. If I can only hold it a short time I know, it is over app. 150 Deg F.

Can anyone recommend one? Mine is cheap enough. How often do you check the temp? About once a week. If you use one, has it improved your composting techniques? Probably not.
John

Here is a link that might be useful: Johns Journal

I use one, but only because a neighbor bough a pallet of "stuff" at an auction and one of the things was a compost thermometer. I was the only person he knew who composts, so I got it.

I leave it in the compost and check it when I walk past. It hasn't really changed any of my composting techniques, but it's kind of interesting to see how hot the compost gets.

I did buy one when I started composting throughout the winter. It was a real aid at the time and I was surprised to see that the compost could maintain temperatures ranging from 60F to 100F even in the dead of winter if properly managed.

Now I use it as a curiosity and have bpgreen's attitude in that it's "interesting to see how hot the compost gets" and how long a time it can stay at a particular temperature.

Hi, Chris in Ca -- After trying to use an instant read thermometer then a meat thermometer on my pile, I finally ordered one from Lee Valley Tools.
It's 20 inches long, weatherproof, and right now it's out in the pile in the rain and still registering almost 120 degrees. I turned the pile yesterday and harvested some beautiful compost to put on my lawn.
I think I'd rather be playing with the whole compost thing than almost anything else. Who knew Rot Happens could be so much fun?
Sunny

Maybe a curiosity, it does make the process more interesting and fun.

When I make a sizable addition, usually about once every week or two, I flip the pile, adjust moisture, and the temp usually rises to about 150 in a day or two. I check every few days and don't mix or otherwise disturb the pile. After the temp falls to about 100, I flip and add stuff again.

So, I guess I do use it as a guide for when to flip.

Karen

I check my compost piles once a day if they are running hot. No need to check that often, by now I've got a pretty good feeling for where the temp is. I just like to. Only once did I get a real surprise, when winter snow had melted and killed the core heat with too much water. Mostly the therm. readings give me a heads up on when it the best day to turn the pile, when the air or water is gone and its time to turn, and when the core is 130F+ so I can add problematic stuff in the core like fish parts or smelly stuff.

I paid $15 for my 18" compost therm. at a good urban garden/feed store. More garden places will not have them.

Since none of my seven compost piles is over 24" in height, an 18" therm. is all I need.

I would recommend a inexpensive compost therm. for many compost users. The highest core heat I've recorded is 165F. According to compost info, temps over 155F are not a benefit.

I'm using a kitchen meat probe right now - $4 from WM - mostly for the sake of my curiosity. And as a reminder not to stir too often -- there are days that I'd just want to play around in it to see what is still recognizable.

I will say that being able to know the temp has made me feel more like the pile is working correctly. I know that everything rots and all that and that the temp plays a bigger part in how long it takes, etc., etc. But before I started using it, I was overwatering the pile -- which I discovered when I relayered everything a while back with a load of UCG. I didn't have compost at the bottom, I had a bog.

Nope, I know what cold feels like. lol. Seriously, learn to do it like your checking an oven or a BBQ grill's heat. But, then I'm very fugal. (cheap)
Sudzy

I think a thermometer is only really necessary if you are managing manure, weeds, or diseased waste. I'm a lazy composter, so I leave out the questionable items and just pile everything

I designated an extra kitchen thermometer that I got on clearance as the compost thermometer. Once in a while when it gets cooking, its fun to take the temperature. I dont get the "core" temp, cuz it isnt long enough.

You can DEFINITELY tell without the thermometer when its hot tho, just dig in a little with a shovel and hold your hand over it.

I use an old candy thermometer. I take the temp just for fun.

For years I used an 18" probe thermometer with a nice simple dial in degrees F and C, which cost $20. Then some fool (alright the same person), who knows not to run with scissors, ran with the thermometer and dropped it on a rock, breaking the face. I used it that way for a couple of years before looking around for another one. The same one was no longer available so I got the rather inferior Lee Valley one, which encourages very hot composting - which I'm against - by telling you which composting temp. range you're in.

I usually do batch composting, and turn the pile only once, if that. I take the temp of the pile in the first couple of weeks to see how well I've built it. If it heats up into the 120-130F range I know I've done a good job of layering materials, and there's good moisture and aeration, so in a sense, the thermometer has trained me to be a better composter.

IMO even $30 - the price of three movies - is cheap for something that lasts for years, and quickly gives you a glimpse into the inside workings of a pile - you can almost see what the bacteria are up to. Impress friends, amaze kids, maybe get a few of them hooked on composting.

A two or three-foot length of reebar, left in the pile for an hour or so, will give you a good idea of the heat in there too.