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Compost very hot - too much nitrogen?

14 years ago

I searched to see if anyone else posted about this, and it looks like most temperature related compost problems are the opposite - but here goes:

I want to have killer, awesome compost. Like everyone does. So I went out to a little FFA farm and got 15 bags (50 to 75 lbs each) of mixed animal manures. The kind teenager who helped me was confident that I was taking from the "goat and sheep" area of the pile.

Then I layered the manure, like a lasagna, with the green goods in the compost and even added a two 64 gallon containers of lettuce, onion, and avocado skins from a local restaurant.

I lovingly turned the compost completely (into a new bin) once a week. It looks very good, but the problem is it is very hot - over 140 degrees - and not cooling down. It has been this hot for weeks and weeks now. Since it was looking so awesome, though, I used some a few days ago - and the plants that touched it died! Shriveled right up and dried out.

I am kind of confused about whether or not I killed the plants with heat of the compost or if maybe the heat of the compost means I killed the plants with an overload of nitrogen.

Comments (19)

  • 14 years ago

    I've attached a related thread about high composting temperatures. Give your pile saome time to cool and odds are you will havce great final product.

    Here is a link that might be useful: hot compost thread

  • 14 years ago

    Temperatures in the 135 to 145 range are what most composters look for when they are trying for hot compost , so you are in that range. Some people find temperatures up to 160, but much over that can present problems. Temperatures over 200 degrees F can cause the compost pile to self combust.
    You can maintain that temperature for a few days to help kill off any disease pathogens there may be but then you will want to turn your compost pile to, 1. redistribute the material so more will get digested, 2. help aerate the compost, 3. maybe add moisture if needed, and 4. to lower that temperature.

  • 14 years ago

    It sounds like a good pile, hopefully you are adding browns also. If it is still too hot, it needs to cure longer before you add it to plants. I don't add fresh manure, I use starbucks coffee grounds as my main source of greens. I guess manure made compost cures much more slowly. I don't know what the time line could be. You can figure it out by trail and error. Takes notes.

  • 14 years ago

    Thanks everyone! I will wait for it to cool before using it again so I don't kill the plants that touch it. And I'm on the look out for some browns to add to it. I have a lot of shredded bark I can add, maybe that will help.

  • 14 years ago

    I would use the shredded bark for mulch but not if it is still green. That is prob what killed your plants.

  • 14 years ago

    If you have brown paper bags from the grocery store, run them into a paper shearer and that is free browns. Of course, in Oct. they are going to start charging 10 cents a bag here. Do you have any way to get some brown leaves? I just buy sheared bagged wood, because free browns are hard to get.

  • 14 years ago

    I try not to use any energy that cost money to make compost so I just crumple my paper bags and feel they add air pockets for my microbes to breath a bit longer.

    Egg crates and other things also add air pockets to the pile :)

  • 14 years ago

    I don't have paper bags - I use fabric bags for shopping. I also can't seem to find leaves right now but I do have a big pile of bark mulch that has been sitting in full sun for well over a year. It started out as a small bark mulch last summer but anything that is under the first few inches became fine bark over the last year. I have been practically wrecking my car because every time I pass an abandoned lot because I'm peering to see if they have a pile of brown refuse tucked away somewhere... :)

  • 14 years ago

    I was driving past a feed store and I saw bales of straw which reminded me you can buy a bale of straw. I have done it, but it so much work to process compared to bagged sheared wood, but it might be good for your case. I think mushroom compost is manure and straw.

    Here is a link that might be useful: photo of straw in compost

  • 14 years ago

    I have problems finding browns as well. I take my own bags to the store, we don't use any disposable napkins, towels or plates. Any sort of cardboard packaging, junk mail, receipts and paper I come across get shredded and added to my compost. I supplement all that with wood chunks to keep it under control. For a family of 5 we take out one bag of trash a week. Look around your house and I'm betting you'll come across some sources. Dryer lint, worn out rags, etc...

  • 14 years ago

    I would never recommend anyone use composting material that was still hot. Personally, I will not let any compost off my facility until the heat phase has completed and an extended curing period has elapsed. There is absolutely no reason to risk ruining someones garden IMO.

    Lloyd

  • 14 years ago

    I get the feeling that coffee grounds is different from manure composting. I never had burning, and often harvest weekly. Once a week or every two weeks, I literate some of the compost from the bins. Sometimes it goes in curing bin, but sometimes I just use it for planting or as a top layer.
    But, it is not hot to the touch when I use it at all. My heat is very short lived with the coffee. It may only last two or three days.

  • 14 years ago

    I'm guessing the C:N ratio is quite different, along with the form the nitrogen is in. Manure probably produces something at levels toxic to plants during the process. Ammonia for example. Whereas weaker greens like coffee grounds are more plant-friendly during their slower breakdown process.

  • 14 years ago

    Ammonia is not at all toxic to plants. In fact, ammonia is exactly what I spray to kill slugs found on my plants. Give it a try.

  • 14 years ago

    I bought a bag of that steer manure once, but it was already composted with straw. It did not actually heat the bin up at all. I was actually looking for a easy cheap way to get the bin really hot and it failed miserably. It was heat neutral, but fresh manure from a farm would be different. Fresh chicken and turkey poop can really burn plants. I don't know the reason why.

  • 14 years ago

    I bought a bag of that steer manure once, but it was already composted with straw. It did not actually heat the bin up at all. I was actually looking for a easy cheap way to get the bin really hot and it failed miserably. It was heat neutral, but fresh manure from a farm would be different. Fresh chicken and turkey poop can really burn plants. I don't know the reason why.

  • 14 years ago

    I am nearly certain that bagged steer manure would already be composted. I know that the kind I have bought in the past has been labeled as such. Perhaps that's why it didn't heat it up very much.

    I don't know why, but there simply isn't any straw for sale in the area right now. I have been on the classifieds nearly daily with no luck. There are several sources 2 hrs north or 2 hrs south of me, but I can't justify a road trip for straw when there must be browns near me and when I have this big pile of shredded bark.

    I turned the compost again today and added layers of the bark mulch to it. Much of it has broken down so much it is a fine powder.

    I actually did kill two cucumber plants with the hot compost, which seems incredibly stupid now but at the time I thought, "Oh, it is probably only hot because it is in this great big pile. It will cool down when I spread it out." It was practically burning my hands as I spread it and admittedly, I did think to myself that it was perhaps not a very good idea. This is my first experience with garden-made compost and I'm loving it!

  • 14 years ago

    BTW coffee grounds are nearly compost already. I never bother with composting them, just apply directly to plants. The plants LOVE coffee grounds.

  • 14 years ago

    Right, it won't be hot when you spread it out, but it will still be hot in the sense that is killing your plants. Did you check for live stock and feed stores?

    I am going to suggest my top product for browns. Master Black Forest Compost. I use it as a brown in my bins. It is expensive, but it is compressed, so one bag can go further then the small size uncompressed bag. It is woody, but the wood is finely ground. There are no big pieces of wood that will slow you down. If I can't find this I use Kellogs Amend that you can get at home depot. But Master Black Forest Compost is better and makes better compost. I think the last bag I used of Kelloggs amend that dandelions seeds in it. I used it on plants without composting it one time, and I got millions of dandelions. But, if I compost it first with the coffee, I don't get an many dandelions. But, if you use a mulch with big pieces you have to keep screening them out, so it is just more time consuming. A microbark will work. The pieces need to be really small, but not as small as saw dust.

    There is probably also a time frame you need to discover before you can use this compost. If you are not adding browns it won't be processing itself on the way to becoming cooler. A year would be safe, I guess, like Lloyd says. He would know.

    Here is a link that might be useful: Master Black Forest Compost