skip to main content

Soil, Compost & Mulch

Compost: Hot hot/how long to kill the 'bad guys'

16 years ago

Before this year, I never had a compost thermometer, so I never knew how hot the compost got.

I wouldn't add things like meat to the pile unless it was really hot. I never knew how hot, but if it was hot enough that I felt a blast of heat when I turned it and it was 90+ degrees out, I figured it was probably hot enough (added a couple of steaks that were in a freezer during a power outage and found no trace three days later).

My last batch of compost never got any hotter than 145 degrees that I saw, but it was between 135 and 145 for a couple of weeks. The batch I started on Sunday was at 152 earlier this evening.

This is mostly academic for me at this point, because I'm using this compost to try to keep a tree alive and not using it in a vegetable garden. But I'm still curious.

Is there some kind of sliding scale, like 135 for 2 weeks, 140 for 10 days, 145 for a week, 150 for 3 days, 160 for 1 day (or something like that)? Or is there some lower limit that it needs to hit to be sure I kill all the pathogens?

Sort by:Oldest

Comments (3)

blutranes
16 years ago
From the Compost Guide web site:

"The following information is for the highly managed pile and the optimum finished compost in the shortest amount of time. Decomposition occurs most efficiently when the temperature inside the pile is between 104 degrees F and 131 degrees F. Compost thermometers are available at garden shops and nurseries. It is best not to turn the pile while it is between these temperatures, but rather when the temperature is below 104 degrees F or above 131 degrees F. This keeps the pile operating at its peak. Most disease pathogens die when exposed to 131 degrees for 10-15 minutes, though some weed seeds are killed only when they're heated to between 140 degrees and 150 degrees. If weed seeds are a problem, let the pile reach 150 degrees during the first heating period, then drop back down to the original temperature range. Maintaining temperatures above 131 degrees can kill the decomposing microbes."

I have read different information, but this is what I came across first. The "Attra" web site has good information about composting disease material I do recall, you may want to check there as wellÂ

Blutranes

Here is a link that might be useful: How To Make Compost
bpgreen
Original Author
16 years ago
Thanks for the info. This is the first year I've had a compost thermometer, so I've never known how hot it was getting before. It's kind of interesting to see just how hot it gets.

I just noticed that I originally posted with "Hot hot" when I meant "How hot" (argh).
Related Discussions
how to grow veggies in the hot hot hot weather
Q
Comments (12)
My "early" garden was a bust, even with shadecloth on parts of it, though I may have waited too long before shading. I grew 4 kinds of corn, all supposed to be heat & drought tolerant & got nary an ear, but it bloomed. On the other hand, my fall garden did well & I managed to get at least some tomatoes. My winter garden is peculiar--lettuce & some greens bolting, broccoli making loose heads, etc. In January. Just enough cold weather for my cabbage to start heading finally. I have planted a couple of cool weather tomatoes in hopes they will survive, but the others stay in for now. Most of the black tomatoes will continue to produce in heat & a few others. I find myself freezing more now so I know I will have it. Last year was a sure cure for complacency!
...See More
Hot Hot Hot
Q
Comments (25)
I can't bring myself to photograph them, but most of my roses look like HoovB's example. The biggest bloom ever, here, for R. banksia lutea was dried to tiny yellow crisps. And while poor "Grandmother's Hat" and "De la Vina Mystery" keep pumping out blooms, they turn into potpourri as they open. :-( Secret Garden Musk Climber has produced a massive blast of white blooms -- but don't look to closely . . . the dry air has crisped the lovely once-yellow stamens. "Historic Powell House" (?'Baronne Prevost'?) is a rare bright spot, and I sure welcome it.
...See More
Hot compost pile cooled down REAL fast...
Q
Comments (14)
Im thinking after reading this two things. One my pile wasnt big enough in the first place and second after getting it to 130 and not getting it there again all winter that by spring it was done. Also Ive read that once your pile is finished that when it cools then worms move in and finish the pile actually making it darker. Im also gathering that especially at first you should turn it every 3-4 days and that the turning process during this period will help heat it up. Im just not sure how to gather more debris for keeping the pile hot once the pile start going down.
...See More
How 'hot' is too hot?
Q
Comments (9)
Nice pad, estreya! Anyway, I'm gonna go out on a limb and give you a little word of caution... all compost is NOT created equal. Do you know what this compost was made from? It looks like possibly wood shavings and some kind of manure. That's fine for compost that has been completely digested and cured. But I'm looking at what appears to be a significant amount of uncomposted wood fibers. Tilling this into the soil MAY cause problems (or may not... that's the thing about unfinished compost - you never know for sure what the final product will be or how long it will take to get there). It's tempting to think that manure, with a low C:N ratio and wood shavings, with a high C:N ratio, would balance out into a nice happy mix. And in the long run they will. But in the short term, nitrogen levels can swing wildly. A worst case scenario would be that the high initial ammonia content burns existing plants, but then the nitrogen levels drop rapidly next spring and now you are nitrogen deficient. OTOH, a best case scenario is that the nitrogen stays put long enough for the wood to decompose and everything grows wonderfully. Probably the safest thing to do is to use it as a mulch instead of tilling it in. If you feel compelled to till it in, then just keep an eye on plant growth and see how they respond. If you're tilling this in for a garden next year, then burning won't be a problem. Watch instead for possible nitrogen depletion, and have a bag of blood meal or something like that on hand in case things look poosley. And don't worry - in the long run it will be fine. It will probably be fine in the short run too, but just be watchful. -Diggity
...See More
kqcrna
16 years ago
Thank you bpgreen for asking the question, and Blutranes for your answer and link. I have wondered about this too. I get my pile up to 140 to 150 degrees, but never knew how high or for what period of time it needed to be held. Very useful information.

Karen

Related Stories

GARDENING GUIDES Get on a Composting Kick (Hello, Free Fertilizer!)

By Matt Kilburn

Quit shelling out for pricey substitutes that aren’t even as good. Here’s how to give your soil the best while lightening your trash load

MOST POPULAR The Perfect Houseplant for People Who Kill Houseplants

By creative jewish mom.com

If you can fill a jar with water, you can keep golden pothos vine happy — and it will pay you back with cleaner air and a greener home

LIVING ROOMS Drop In on a Hot Comeback With a Sunken Living Room

By Mitchell Parker

Take the plunge into a new kind of practicality with an interior design feature that has a rich history

COLOR 4 Hot Color Trends to Consider for 2013

By Jennifer Ott Design

Bring some zing to your rooms for the new year, with high-energy shades that open the eyes and awaken the spirit

GARDENING AND LANDSCAPING 12 Naturally Beautiful Hot Tubs

By Laura Gaskill

Prefer a no-plastic look for your patio or yard? Wood, stone and concrete make these hot tubs fit right in with nature

KITCHEN DESIGN Hot Ideas and Tips for Coffee and Tea Stations

By Tiffany Carboni

Let options like drawer inserts and built-in coffeemakers percolate now, so your hot-drinks station can best serve holiday guests

KITCHEN DESIGN Using White Marble: Hot Debate Over a Classic Beauty

By Beth Dotolo, ASID, RID, NCIDQ

Do you love perfection or patina? Here's how to see if marble's right for you

MUDROOMS Room of the Day: This Mudroom Is Just Plain Hot

By Mary Jo Bowling

Wait till you see what’s behind the hooks and bins in this genius family drop zone

MOVING Tips for Winning a Bidding War in a Hot Home Market

By Christine Tusher

Cash isn’t always king in a bidding war. Get the home you want without blowing your budget, using these Realtor-tested strategies

REMODELING GUIDES 5 Hot Tips for Home Saunas

By Lisa Frederick

Bask in your very own heated haven, indoors or out. This overview will get you off to a glowing start

Sponsored

Fine Designs & Interiors, Ltd.

28 Reviews

Columbus Leading Interior Designer - Best of Houzz 2014-2022

More Discussions

food for earthwroms?

1

Best soil testing labs?

2

Pine Bark - Break Down

1

Least bad weeds for compost

17

Need advice - got into some ‘DIRT’

13