How hot does your compost get? (pics)

TomNJ · May 22, 2010

This year I borrowed my neighbor's chipper/shredder and ran tons of leaves through it, pulverizing them to near powder. I then intimately mixed the shredded leaves by hand with an equal volume of fresh grass clippings and built the pile all at once, adding limestone, lawn fertilizer, and water every six inches. Finished pile is 4' x 4' x 3' (~50 cubic feet). I then stuck a digital meat thermometer in the center about 5" deep.

The temperature rose to 140F over four days, then began slowly cooling (133F after seven days). It is probably hotter in the center of the pile but I can't measure it that deep. When I pushed the thermometer another two inches deep it did go up a couple of degrees.

How hot does your pile get, and how do you measure it?

TomNJ

heirloomdaddy · May 22, 2010

that's a killer looking pile. I'm jealous. Mine is suffering due to lack of shredding...but still producing some compost. Slowly.

kath · February 21, 2018

Quote:

Originally Posted by heirloomdaddy

that's a killer looking pile. I'm jealous. Mine is suffering due to lack of shredding...but still producing some compost. Slowly.

Ditto! Never measured mine.

Sherry_AK · May 22, 2010

Ours usually gets to 150° and we measure with a compost thermometer. We also have some deep fryer thermometers (from WalMart in the BBQ section) which were inexpensive and work fairly well. They don't reach in as far as the compost thermometer, but probably a good bit further than your meat thermometer. We have lots of horse, chicken, sheep, etc., manure in our piles, so it heats pretty well.

Sherry

**mdvpc** · May 22, 2010

I use a nature mill composter-my wife wont let me have a pile. And I always do what she says. The composter cooks the "pile" up to 150 degrees.

David Marek · May 23, 2010

Nice bin.

If you turn the pile at least once or twice it will stay hot, decompose faster and gives the outside a chance to become part of the inside to kill off many weeds and disease organisms.

I had an aerobic (the bacteria breathe oxygen like us) "batch" pile get up to 165 after the second turning, but 150-155 for a week or two is about average followed by a slow two or three week cool down. At 170 or higher the good guys start to die off and nutrients begin to volatilize. I take the reading with a short meat thermometer from the center of the pile when I turn it.

tjg911 · May 23, 2010

i've yet to get a hot pile here in 10 years but i don't have grass clipping i rely on green stuff from the garden and it's not shredded. at my other house i had a small lawn and bagged the grass clippings. my pile was about 5' X 4' X 3' and it got HOT! when i'd turn it steam would pour out and no lie you couldn't get near the pile! i made compost fast. here it takes time w/o grass clippings.

December 17, 2010

Many comments on compost threads suggest the heat in a compost pile is the mechanism which kills weed and grass seed in the pile. Many people also say their compost piles never seem to generate heat, but the seeds seem to be killed over time anyhow.

I wonder if the moisture content and the warm (not hot) temps inside a compost pile cause seed to germinate. Since no sunlight is available, the germinated seed simply dies.

Which is more important in a compost pile, generating enough heat to cook the seed or creating an environment which causes the seed to germinate?

Ted

**Mischka** · December 17, 2010

My vote is for generating heat sufficient enough to kill the germplasm within the seeds.

Weed seed kept at a temp above 140°F for an extended period of time will lose germination viability.

December 17, 2010

Quote:

Originally Posted by Mischka

My vote is for generating heat sufficient enough to kill the germplasm within the seeds.

Weed seed kept at a temp above 140°F for an extended period of time will lose germination viability.

What is "an extended period"? A few hours or a few days?

Will the high heat not not degrade the bacterial colony that caused the high heat?

Will the high heat not degrade the nutritional value of the compost exposed to the heat for an extended period?

Ted

acorn · February 24, 2011

The highest my pile has ever got was a little over 160 here in AZ. Was early fall and I was turning every 2 days in order to speed up the process. Also was using black plastic sheet over the pile to keep moisture in. I use an 18" long probe that I connect to my Voltmeter. the meter has a setting for temp and uses a certain standard type probes. I got the long one from McMaster for another project but it works well for this also.

- Aaron

mjc · February 24, 2011

Quote:

Originally Posted by tedln

What is "an extended period"? A few hours or a few days?

A few hours would get some to most. A few days will get most to all. About a week will get everything.

Quote:

Originally Posted by tedln

Will the high heat not not degrade the bacterial colony that caused the high heat?

Actually, yes. But not completely wipe it out. But, without the addition of fresh material, it will die off anyway...and the bacteria responsible are common in all soils, so there is a ready supply to move in and 'be fruitful and multiply (or is that divide?).

Quote:

Originally Posted by tedln

Will the high heat not degrade the nutritional value of the compost exposed to the heat for an extended period?

Ted

No. It actually transforms some of the nutrients into more 'useful' forms. Water will leach out far more nutrients.

Too Tall Toms · November 11, 2011

160 F compost??? Wow....the hottest my compost ever got was 120. It cooled down and when I added horse manure and other compostables, the highest it got was 80F

Too Tall Toms · November 15, 2011

Hey....since I added alpaca and rabbit manure to my compost over the weekend, the temp of my compost pile is at 130F! That's excellent! It started out at about 90F and it's been averaging about a 10F a day increase since Saturday.

dustyrivergarden · November 18, 2011

My first post on this form and it might as well be talking about compost. lol As a guy that has only been composting for a couple of years is there one major no no for the compost pile that rookies try to toss in. So far I have had great success but one never knows...

May 22, 2010	#5
mdvpc Tomatoville® Moderator Join Date: Jan 2006 Location: San Antonio, Texas Posts: 4,386	I use a nature mill composter-my wife wont let me have a pile. And I always do what she says. The composter cooks the "pile" up to 150 degrees. __________________ Michael

May 23, 2010	#7
tjg911 Tomatovillian™ Join Date: Feb 2006 Location: zone 5b northwest connecticut Posts: 2,570	i've yet to get a hot pile here in 10 years but i don't have grass clipping i rely on green stuff from the garden and it's not shredded. at my other house i had a small lawn and bagged the grass clippings. my pile was about 5' X 4' X 3' and it got HOT! when i'd turn it steam would pour out and no lie you couldn't get near the pile! i made compost fast. here it takes time w/o grass clippings. __________________ I need a hero I’m holding out for a hero ‘til the end of the night He’s gotta be strong And he’s gotta be fast And he’s gotta be fresh from the fight I need a hero I’m holding out for a hero ‘til the morning light He’s gotta be sure And it’s gotta be soon And he’s gotta be larger than life

December 17, 2010	#9
Mischka Tomatoville® Administrator Join Date: Jan 2006 Location: The Bay State Posts: 3,207	My vote is for generating heat sufficient enough to kill the germplasm within the seeds. Weed seed kept at a temp above 140°F for an extended period of time will lose germination viability. __________________ Mischka One last word of farewell, Dear Master and Mistress. Whenever you visit my grave, say to yourselves with regret but also with happiness in your hearts at the remembrance of my long happy life with you: "Here lies one who loved us and whom we loved." No matter how deep my sleep I shall hear you, and not all the power of death can keep my spirit from wagging a grateful tail.

May 22, 2010	#2
heirloomdaddy Tomatovillian™ Join Date: Feb 2010 Location: Los Angeles Z10 Posts: 291	that's a killer looking pile. I'm jealous. Mine is suffering due to lack of shredding...but still producing some compost. Slowly.

May 22, 2010	#4
Sherry_AK Tomatovillian™ Join Date: Jan 2006 Location: Alaska Zone 3/4 Posts: 1,857	Ours usually gets to 150° and we measure with a compost thermometer. We also have some deep fryer thermometers (from WalMart in the BBQ section) which were inexpensive and work fairly well. They don't reach in as far as the compost thermometer, but probably a good bit further than your meat thermometer. We have lots of horse, chicken, sheep, etc., manure in our piles, so it heats pretty well. Sherry

May 23, 2010	#6
David Marek Tomatovillian™ Join Date: Jan 2010 Location: St Charles, IL zone 5a Posts: 142	Nice bin. If you turn the pile at least once or twice it will stay hot, decompose faster and gives the outside a chance to become part of the inside to kill off many weeds and disease organisms. I had an aerobic (the bacteria breathe oxygen like us) "batch" pile get up to 165 after the second turning, but 150-155 for a week or two is about average followed by a slow two or three week cool down. At 170 or higher the good guys start to die off and nutrients begin to volatilize. I take the reading with a short meat thermometer from the center of the pile when I turn it.

December 17, 2010	#8
tedln Guest Posts: n/a	Many comments on compost threads suggest the heat in a compost pile is the mechanism which kills weed and grass seed in the pile. Many people also say their compost piles never seem to generate heat, but the seeds seem to be killed over time anyhow. I wonder if the moisture content and the warm (not hot) temps inside a compost pile cause seed to germinate. Since no sunlight is available, the germinated seed simply dies. Which is more important in a compost pile, generating enough heat to cook the seed or creating an environment which causes the seed to germinate? Ted

February 24, 2011	#11
acorn Tomatovillian™ Join Date: Feb 2011 Location: Tucson, AZ Posts: 25	The highest my pile has ever got was a little over 160 here in AZ. Was early fall and I was turning every 2 days in order to speed up the process. Also was using black plastic sheet over the pile to keep moisture in. I use an 18" long probe that I connect to my Voltmeter. the meter has a setting for temp and uses a certain standard type probes. I got the long one from McMaster for another project but it works well for this also. - Aaron

November 11, 2011	#13
Too Tall Toms Tomatovillian™ Join Date: Nov 2011 Location: Pennsylvania Posts: 116	160 F compost??? Wow....the hottest my compost ever got was 120. It cooled down and when I added horse manure and other compostables, the highest it got was 80F

November 15, 2011	#14
Too Tall Toms Tomatovillian™ Join Date: Nov 2011 Location: Pennsylvania Posts: 116	Hey....since I added alpaca and rabbit manure to my compost over the weekend, the temp of my compost pile is at 130F! That's excellent! It started out at about 90F and it's been averaging about a 10F a day increase since Saturday.

November 18, 2011	#15
dustyrivergarden Tomatovillian™ Join Date: Nov 2011 Location: Holbrook, Az zone 5 Posts: 157	My first post on this form and it might as well be talking about compost. lol As a guy that has only been composting for a couple of years is there one major no no for the compost pile that rookies try to toss in. So far I have had great success but one never knows...