Composting - mixed cooked and raw food.

[Butterscotch]

I have 3 compost bins in the garden and we throw all our food scraps in. We do not add any meat, but anything else goes.
In the last couple of weeks I have had three different people say they have heard you shouldn't mix up cooked food (eg. left over pasta) with the raw food (vegetable peel, egg shells, etc). BUT it is ok to add used coffee grinds and tea bags.

Do any of you know anything more about this? Educate me!

[Zuul]

This is one of those things that "everyone knows" and yet nobody knows why.

As far as I'm aware, it started being passed around as advice to keep rats and mice from going after your compost. It'll also have a stronger smell, which is more likely to attract vermin. Additionally, it may contain animal products that most people don't think about, but from your examples it sounds like it would be fine. If you want to avoid any vermin or smell problems, just make sure the cooked food you add is buried in the compost, rather than temptingly on top.

I've composted everything except for meat--including eggs!--and have never had any problems. I just make sure to put a layer of something over it.

[Malaky]

Yeah that's what I've always heard too from various folks, but i'm curious to know if there is some truth behind that.

(If I never put cooked food in the compost, it's because the dog, cats and hens pretty much eat any left over anyway)

[Alien Crouton]

The problem is not whether it is cooked. The problem is that some types of food attract vermin and scavengers. I experimented with throwing out grain-based foods (bread, pasta, etc) and found that it attracted many small bugs that were small enough to migrate through the screen vents of my compost tumbler. I never had bug problems as long as I excluded meat, dairy, and grain from my compost.

Other food waste to avoid:
* oils - not friendly to the worms and other animals that process your compost
* onion - smelly decomposition products
* sugars and sugary fruits like oranges - bug problems similar to grain
* excess citrus fruit - makes the pH more acidic

Oddly, I expected problems with spoiled potatoes due to starch content, but never had any problems. I guess potatoes are naturally adapted to being in those sorts of conditions.

Helpful additives:
* Garden lime (calcium carbonate)
* Grass clippings (for hot composting)
* Fresh horse manure (likewise, for hot composting)

[Vox Imperatoris]

I don't know anything about this: why not meat? Does it just attract too many pests?

[vison]

Meat attracts pests and it also stinks to high heaven as it decomposes. It should be put deep into the pile, if you're going to do it. In The Omnivore's Dilemma, the author describes the composting practices at Polyface Farm (think that's the right name) and they composted chicken guts, etc., after killing and processing chickens.

My composting is rather lackadaisical, I chuck nearly everything on the pile and all summer long I put grass clippings and manure on it, and sawdust, whatever I have. If you can get mushroom manure - after the mushroom farm is done with it - it makes a nice additive. It is mostly composted horse manure/straw. Doesn't smell bad, either. In the fall, I put a lot of leaves on the compost, including Oak leaves and that's supposed to be a no-no, but it doesn't seem to hurt anything.

[Hatshepsut]

Thanks for asking, I've been wondering the same thing. Without knowing why except "it sez so on the internet," I have excluded all cooked products and all animal products except egg shells from my composting. Since it almost never stinks, and my plants seem pretty happy with the first couple of batches, I guess I won't change anything.

My open/cold compost pile attracts tons of bugs though - gnats, ants, and worms (no flies, thank goodness). I've never thought of this as a problem, just part of the natural decomp process (not to mention part of living in the tropics). Does their presence mean I'm doing something wrong?

[McNutty]

Seattle recently changed their recycling/garbage/composting service rules, and they have started allowing meat in the composting bins (these are big bins that the city comes and empties into a truck, like garbage and recycling). The paperwork they sent out announcing this change had a Q&A section, and one of the questions was along the lines of "I've always heard I shouldn't throw meat in my compost pile...why can we put meat in the city bins?" and the answer given was that a typical backyard compost pile doesn't get hot enough to kill all the food-borne pathogens in the meat, but that the large-scale municipal composting operation does.

[Alien Crouton]

Seattle recently changed their recycling/garbage/composting service rules, and they have started allowing meat in the composting bins (these are big bins that the city comes and empties into a truck, like garbage and recycling). The paperwork they sent out announcing this change had a Q&A section, and one of the questions was along the lines of "I've always heard I shouldn't throw meat in my compost pile...why can we put meat in the city bins?" and the answer given was that a typical backyard compost pile doesn't get hot enough to kill all the food-borne pathogens in the meat, but that the large-scale municipal composting operation does.

Yes... as I alluded earlier, a hot-composting operation is quite effective at foot disposal. In the summertime when I have lots of grass clippings to spare, I can put nearly anything under a couple bushels of damp grass clippings. The pile heats up to several hundred degrees, and is completely composted in a couple of days. This also works with fresh horse manure. However in the wintertime I have to be much more conservative about what goes in the pile, because the ambient temperature is lower and I have less green input available. In fact, toward the last 1-2 months of winter I have raw food actually accumulating in the pile, and I am REALLY glad to get that first load of grass clippings on there to cook it down. Even though there's no meat in it, around February-March our pile becomes ground zero for the local Kitty Fight Club.

[Butterscotch]

Thanks folks! I was wondering why we can send our meat scraps to the council compost, but why we don't put it in the garden one! Interesting about the grass clippings. My Granddad always said you shouldnìt put grass clippings in your compost as you get too many grass seeds in your flower beds and veg garden that way. Do you find that is a problem?

Looks like we can keep on composting the left overs though. We live out in the country and mice and rats are fairly common anyway, that's why we have the cats!

Yes... as I alluded earlier, a hot-composting operation is quite effective at foot disposal. In the summertime when I have lots of grass clippings to spare, I can put nearly anything under a couple bushels of damp grass clippings. The pile heats up to several hundred degrees, and is completely composted in a couple of days.

Bolding mine. Sorry, usually I wouldn't bring attention to someone else's typo, but that there, that's a classic!!

[Bear_Nenno]

What do you do with your compost? Unless a person is a gardener, I don't get it. But it seems like there are a lot more composters than farmers and gardeners, so there's got to be something else to it.

[Butterscotch]

It goes into our vegetable garden, fruit trees and flower beds. We use all we make!

[Alien Crouton]

Interesting about the grass clippings. My Granddad always said you shouldnìt put grass clippings in your compost as you get too many grass seeds in your flower beds and veg garden that way. Do you find that is a problem?

A typical ornamental lawn doesn't get long enough to produce seeds. Plus if you're composting damp grass as I said, then the pile heats up enough to kill most weed and grass seed inside. Any that don't get killed will germinate, die, and re-compost inside the pile.

[Butterscotch]

Ah, that helps, thank you! We have a far-from-ornamental lawn but I'm sure the summer temps here will be enough to kill off any seeds just like you say.

[Green Bean]

The reason "cooked food" is generally excluded from basic rules is that it simplifies things. The three things that cooked food might include which may present a problem are:
1. Fat. Nominal amounts are okay. More than that gums up the works.
2. Salt. Salt is bad for soil. Again, nominal amounts are no biggie.
3. Meat. Meat can absolutely be composted, but it requires some care and expertise.

So, beginner composting directions just say to exclude cooked food, which is a real shame! And I don't know why mixing cooked and raw would be any sort of a problem. As long as the green/brown mixture is okay, then what difference would it make?

The problem is not whether it is cooked. The problem is that some types of food attract vermin and scavengers. I experimented with throwing out grain-based foods (bread, pasta, etc) and found that it attracted many small bugs that were small enough to migrate through the screen vents of my compost tumbler. I never had bug problems as long as I excluded meat, dairy, and grain from my compost.

Please don't take the above (or the rest of the post) as gospel. Everybody's mileage varies on stuff like this. I always had the best of results with grain products, especially old bread. The wormies loved it. The best thing to do is experiment and see what works best for your particular conditions.

And I'd also recommend two books--The Rodale Guide to Composting and The Humanure Handbook. Now, please don't think I'm suggesting that you start composting your own poop. But the book is a truly excellent guide to more advanced home composting techniques, including a lot of material on the role of hot composting and how to make it happen. Plus, the book is quite amusing.

Yes... as I alluded earlier, a hot-composting operation is quite effective at foot disposal.

Hot lava works better.

What do you do with your compost? Unless a person is a gardener, I don't get it. But it seems like there are a lot more composters than farmers and gardeners, so there's got to be something else to it.

I think the biggest benefit of home composting is that it gets material out of the municipal waste stream. Why spend the resources to send your apple cores and potato peelings to be sealed up in a landfill? The potential environmental benefits of widespread home composting are enormous.

As for what to do with the finished compost? You can sprinkle it over your lawn or spread it under your shrubs or something. Or give it to your neighbor who's into gardening. Wherever it goes, it will will do a hell of a lot more good that it would have done to have shipped the garbage that it's made out of to the landfill.

[McNutty]

Wherever it goes, it will will do a hell of a lot more good that it would have done to have shipped the garbage that it's made out of to the landfill.

This brings up a question which might be getting a little off-topic, but I think about occasionally when I take out the trash these days: we no longer put compostable stuff in the trash, so now our trash is almost exclusively non-recyclable plastic and styrofoam (and thankfully less and less of that stuff even). What impact does this have on landfills? Aside from the issue of how much landfill space you need, wouldn't it be preferable if the stuff going into your landfill had some amount of stuff that can decompose in it? I'm probably not very well informed on landfill technology, but my impression is they mix dirt into the garbage and cover it with a layer of dirt in order to make it more stable and earth-like. Does removing the decomposable components of the garbage make this more difficult?

[Badtz Maru]

The pile heats up to several hundred degrees, and is completely composted in a couple of days.

Are you sure about this? I thought the hottest a compost heap could get due to decomposition was around 180 or so.

[Alien Crouton]

[quote=Badtz Maru]

The pile heats up to several hundred degrees, and is completely composted in a couple of days.

Are you sure about this? I thought the hottest a compost heap could get due to decomposition was around 180 or so.[/quote:5kyyedms]
Ok, well, I stand slightly corrected. Compost heaps can get up to 300F and actually catch fire, if you have a large pile of good hot-composting material like grass or manure, and you don't turn the pile. A well-turned compost pile, or a small household compost pile, will only get up to 110F-160F, the upper range of which is hot enough to let the microbes digest seeds and such.

[Alien Crouton]

What do you do with your compost? Unless a person is a gardener, I don't get it. But it seems like there are a lot more composters than farmers and gardeners, so there's got to be something else to it.

Household compost typically doesn't generate a lot of bulk, so disposing of it isn't a problem. Usually everybody has at least one tree or shrub in their yard where they can spread compost, or they have a neighbor who is more than happy to put it on their flowers or gardens.

For many, the goal isn't producing compost, it's to divert waste from the landfill. The more you compost, the fewer bags of stinking garbage you have sitting on the curb in the sun, and the slower your county landfill reaches capacity.

[Bear_Nenno]

Wow. So now I see why it's such a common thing. I thought it was just for gardeners, so it struck me as odd that I hear about composting more than gardening.

If I had a yard, I would start. I dont even have dirt.

[Alien Crouton]

You don't even need dirt. If you have a bit of spare cash you can buy an enclosed worm composter like can o' worms (worms sold separately) and keep it in a garage or patio. It does not stink or cause vermin problems if you exclude the foods we already discussed (meat, dairy, processed foods, onions, whole garlic). For our household of 2, we never even need to remove the worm castings from the bin. Using the attached valve I just drain off about a quart of liquid every 3 days and pour it where it will do some good.

[Butterscotch]

I'm probably not very well informed on landfill technology, but my impression is they mix dirt into the garbage and cover it with a layer of dirt in order to make it more stable and earth-like. Does removing the decomposable components of the garbage make this more difficult?

I wonder about this. I'd've thought it did make it more difficult. My thinking being based on a piece of rotten fruit in the fruit bowl that makes the other fruit rot more quickly. Surely having rotting things there would speed up the process, but, then if stuff like nappies don't really rot, it isn't as if a piece of rotting fruit will make it mould over and decompose.

Here's another thing about our compost: worms. We don't have any. I've never seen a worm on our garden, even after rain. The soil is rich, we live in a volcanic area, but it is like clay. It is a nightmare to dig when dry because it cooks like terracottaa under the sun, and wet it sticks to your shoes and garden tools until it is inches thick. So we don't have worms in the compost either, we have to wait for the food to break down by itself. Any suggestions?

[Green Bean]

I'm probably not very well informed on landfill technology, but my impression is they mix dirt into the garbage and cover it with a layer of dirt in order to make it more stable and earth-like. Does removing the decomposable components of the garbage make this more difficult?

I'm not sure, but I'd think that it would have the opposite effect. When organic matter decomposes, its volume is reduced significantly. Fill dirt is probably pretty stable. It's likely to have relatively low organic content (which is why they're using it as fill) and what organic content it does have is already probably fully broken down.

I wonder about this. I'd've thought it did make it more difficult. My thinking being based on a piece of rotten fruit in the fruit bowl that makes the other fruit rot more quickly. Surely having rotting things there would speed up the process, but, then if stuff like nappies don't really rot, it isn't as if a piece of rotting fruit will make it mould over and decompose.

All organic matter carries the seeds of its own destruction. In other words, the piece of fresh fruit has bacteria on it that will eventually cause it to rot. But it's true that having a rotting piece of fruit next to it will hasten its decomposition, as the bacteria/molds/etc. are multiplying like mad in the rotting fruit and are therefore swarming around the fresh fruit as well. But all of that is basically irrelevant to a landfill, because most landfills aren't designed to hasten aerobic decomposition.

Here's another thing about our compost: worms. We don't have any. I've never seen a worm on our garden, even after rain. The soil is rich, we live in a volcanic area, but it is like clay. It is a nightmare to dig when dry because it cooks like terracottaa under the sun, and wet it sticks to your shoes and garden tools until it is inches thick. So we don't have worms in the compost either, we have to wait for the food to break down by itself. Any suggestions?

Organic material. Your soil may be rich in nutrients, as clay soils often are, but it needs organic matter to "lighten" it. Compost is ideal. You can increase your compost production quite a bit if you're willing to put a little work into it. Do you live an an area with horses? Because if you get some horse manure (mixture of manure and bedding), pile it up, and turn it over with a fork every now and then, you'll have a pile of really nice compost in a very reasonable amount of time. It won't be the "richest" compost out there, but it will be fabulous for your garden beds. You can also buy bagged stuff to bulk up your compost at garden centers.

For what it's worth, the "cure" for sandy soil and clayey soil is the same--organic matter. Compost is really kind of a garden cure-all.

ETA--I forgot the worms! Generally, as your soil gets better, worms will come on their own. But if your whole area is so clayey, there may not be many worms to come! It might be worth buying some red wigglers to put in your compost bin. (Not fishing worms. You want to get composting worms.) They will eventually colonize your garden beds, either by migration, or just by ending up in the compost that you put in the beds.

[Butterscotch]

Organic material. Your soil may be rich in nutrients, as clay soils often are, but it needs organic matter to "lighten" it. Compost is ideal. You can increase your compost production quite a bit if you're willing to put a little work into it. Do you live an an area with horses? Because if you get some horse manure (mixture of manure and bedding), pile it up, and turn it over with a fork every now and then, you'll have a pile of really nice compost in a very reasonable amount of time. It won't be the "richest" compost out there, but it will be fabulous for your garden beds. You can also buy bagged stuff to bulk up your compost at garden centers.
For what it's worth, the "cure" for sandy soil and clayey soil is the same--organic matter. Compost is really kind of a garden cure-all.
ETA--I forgot the worms! Generally, as your soil gets better, worms will come on their own. But if your whole area is so clayey, there may not be many worms to come! It might be worth buying some red wigglers to put in your compost bin. (Not fishing worms. You want to get composting worms.) They will eventually colonize your garden beds, either by migration, or just by ending up in the compost that you put in the beds.

We have a lot of horses, and live stock around here, I am sure getting hold of manure won't be a problem. Can I mix it in with the food scraps?

Our whole area is clayey. If it helps, the main product grown here is hazlenuts. The trees do very well and there are tree farms all over. But the soil is rock solid come summer. I have thought of buying worms but I have two concerns, one is that they might die off as there really are none up here, there must be a reason for that, although I suppose if they live in the compost and we can give them a suitable environment they should survive. My other concern is brining in an animal species that is not native to the area. We try as much as possible to be environmentally friendly, we don't use any chemicals, we don't buy compost inc ase it has them added, and we are wary of upetting the natural balance where we are. Could compost worms do that?

[Alien Crouton]

We have a lot of horses, and live stock around here, I am sure getting hold of manure won't be a problem. Can I mix it in with the food scraps?

Absolutely. Fresh horse manure is great, it really heats up and completely destroys all food scraps. Weathered horse manure won't heat up the same way, but it's still great compost.

Regarding the previous question on adding dirt, I never put dirt or soil or clay in a compost pile, ever. It doesn't add anything. However, when I start a new pile, I put a few shovels of the old pile in to help seed the microorganisms. Also, leaf litter is good for when you are too heavy on green (nitrogenous) mass and need more brown (carbon) mass. But plain loam or clay? Never. Compacts the pile, you don't want that.

[Butterscotch]

Ok, manure not dirt, check! Now, about buying in worms, what can you advise?

[Alien Crouton]

Ok, manure not dirt, check! Now, about buying in worms, what can you advise?

First, don't add worms to a hot compost pile. If you're using fresh grass trimmings or fresh manure, you'll get temperatures that are high enough to kill worms. The temperature is more than adequate for your composting needs. Weathered manure is fine for cool composting as much of the nitrogen has broken down.

Otherwise, for cool-composting with worms, you can order red wigglers online. These are the ones that will eat your leftovers. Earthworms won't; they are more for improving the tilth of packed soils (hence the name). Red wigglers are also invasive, so if possible try to isolate your pile from wild soil (scrape off the groundcover under it and around it, or better yet use an elevated enclosure.

[Alien Crouton]

On second thought, concerning red wigglers being invasive... I was repeating what I heard, and after going back and checking, it seems they aren't. Nightcrawlers, used as bait worms, are invasive. Red wigglers are native to Europe, but they're not considered a "problem species". So make sure you get red wigglers. If you're in an area with hard-packed clay, you have little concern about your worms going wild. The main thing to avoid is dumping non-native worms in a woodsy area where there is lots of dead organic material laying on the ground.

So, in summary, red wigglers are not invasive, make sure red wigglers are exactly what you're getting, and just to be safe, don't dump any non-native worms in the forest.

Edit: I notice your location says Italy... in that case, don't even worry, since red wigglers are native to Europe.

[Butterscotch]

Thanks, I'm looking into red wrigglers but everything is complicated here! I'm going to get the books mentioned upthread too.

Thanks guys for all your help!

[Stoid]

I have 3 compost bins in the garden and we throw all our food scraps in. We do not add any meat, but anything else goes.
In the last couple of weeks I have had three different people say they have heard you shouldn't mix up cooked food (eg. left over pasta) with the raw food (vegetable peel, egg shells, etc). BUT it is ok to add used coffee grinds and tea bags.

Do any of you know anything more about this? Educate me!

Hooey.

The only things that are genuinely verboten are meat and poop.

[susan]

My landfill info says that that the majority of the landfill is anaerobic, so organic material doesn't break down or help anything, and therefore we should compost or use the city compost bins.

I get sowbugs, gnats, and worms from using any vegetable matter. There isn't a nice sunny spot for my composter, which may contribute, nor do I have either a lawn for clippings or a neighbor with a lawn who doesn't douse it with chemicals that I don't want on my vegetables. I use an organic activator when I think of it, but we send most clippings to the city since our compost isn't hot enough to break down weed seeds or brambles.

[Butterscotch]

Hooey.

The only things that are genuinely verboten are meat and poop.

Whoose poop though? Horse poop is good, right?

[Stoid]

Hooey.

The only things that are genuinely verboten are meat and poop.

Whoose poop though? Horse poop is good, right?

You're right, I wasn't clear. I was thinking dog poop, since that's what I have to make sure to avoid when I rake up the leaves... no CARNIVORE poop. In other words, no meat, whether pre or post-digestion.

[Butterscotch]

You're right, I wasn't clear. I was thinking dog poop, since that's what I have to make sure to avoid when I rake up the leaves... no CARNIVORE poop. In other words, no meat, whether pre or post-digestion.

Ok, that makes sense! Thank you.