Quite often people will have a go at making compost. They will gather together a heap or start loading a bin. Then, after a while, they see lots of flies and there is a bad smell and they ask, why have I got such smelly compost?
Smelly compost is a clear indication that the composting process isn’t working as it should. The problem is easily solved. Smelly compost happens because it’s too wet and soggy. This stops air from getting into the composting mass which leads to an anaerobic digestion rather than composting.
One of the best things you can do to stop smelly compost is to add plenty of wood sawdust or cardboard, for the carbon ‘brown’ factor, and stir it in to the existing smelly heap or bin. This soaks up excess water, and will help to remove some of the excess ‘green’ slimy material.
Green leaves, fresh grass, fresh vegetable waste is high in ‘nitrogen’, and will create bad smells very quickly, if there is not enough ‘brown’ material to both soak up moisture and also ‘balance’ the mixture so that aerobic bacteria can utilize the food much better.
Make sure the compost is ‘fluffed up’, so that air can pass through the material.
This means things like sawdust, shredded cardboard, wood-chip, etc should be added every time you add lush grass clippings or wet vegetable trimmings.
To fluff up your compost heap, just turn it over with a shovel, or if you are making compost in a container, use a mixing tool to open up the material to get air into it. Doing this regularly will accelerate the rotting process and will reduce the risk of smells.
Save your dead autumn leaves somewhere dry, so that you can use them to mix in with fresh green waste during the whole year.
It is really worth having a store of dry dead leaves, shredded cardboard, dry hay, dry straw and wood sawdust or shavings, ready to add to your compost heap, every time you add kitchen waste or lawn-clippings.
OK, it is extra bulk, meaning your heap is bigger to find space for, but you will have much less smell, and much greater yield of good, black compost to use in the garden.
I always find that I never have enough compost, so, any means of increasing the amount of nice black compost, is a good thing.
Some heating of a compost heap should occur, and this shows you have the right conditions ‘in there!’
By making sure your compost heap is not producing bad smells, you are also speeding up the effective composting process, as a result.
You will find that the volume shrinks quite rapidly, this is a good indicator of good composting technique.
Since a lot of moisture is lost from the heap during composting, water being at least 75% of the volume, then we should expect considerable shrinkage, as, conversely, only 25% of the material is dry matter.
A good indicator of optimal composting is the presence of red worms around the heap, especially where the compost is going dark around the base or sides.
Do not allow the compost material to just go compacted, shake it up as soon as you see it packing down.
Never add fish, meat, bones, cooking oil or fats, to a small composting setup in your backyard or patio.
These wastes are just too rich for the system to handle without causing dreadful smells, and attracting pests.
There are ways of composting these wastes, but these involve working on a larger scale with the use of a wormery finishing system.
Follow these simple rules all the time, and you will not get any stinks or bad smells.
Bad smells from smelly soggy compost or smelly compost bin are easy to rectify, and, give you a much more satisfying experience with recycling food waste, if you know, for certain, that you will have a good pile of black compost for your plants and shrubs.
Smelly compost tumbler, how to stop.
No one wants a smelly compost tumbler. There’s an easy way to stop the smell. Just add some carbon ’brown’ material e.g. cardboard or dead leaves and roll the tumbler over. You can do more to stop the smell by adding a sprinkling of hydrated white lime. This will reduce the acidity that makes compost smelly.
Smells almost always come from excess moisture, which stops air circulation in the contents of your tumbler.
If the fresh food wastes start to ferment because of the lack of air (anaerobic fermentation), it produces the organic acids, acetic, propionic and butyric. Butyric acid is the smelly one that you cannot get rid of the smell of, if it gets onto your hands!
Tumblers are great for quick composting smaller amounts of food-waste, and garden trimmings, because it is easy to turn over and aerate the compost regularly.
Make sure the drainage holes are clear and can drain away any excess water, if necessary. Retained moisture is the usual cause of smelly compost.
Usual rules apply for not adding meat and dairy wastes, see above post.
Shred any larger waste leaves to increase the speed of composting.
For a brand new tumbler, make sure you add a shovel-full of old black compost, or some dark topsoil, from where an old compost heap was, years ago. This adds micro-organisms that will get the composting going.
You can buy compost accelerator bacterial mixes, which will ensure a good quick composting. This can be beneficial to add every few months. Do make sure there is enough moisture for the dry powder to become hydrated, and the bugs can come back to life.
Smelly compost heap, what can I do?
A smelly compost heap can be remedied much in the same way as a smelly compost tumbler. A compost heap needs to be dug over. During the digging process add some dry material. Pieces of cardboard, dry dead leaves or sawdust will absorb enough of the moisture in the heap to encourage the composting process to proceed.
Get it fluffed up, so air travels around and through the heap easily.
Make sure liquids can drain away from the heap (into a grassy area, if possible). It is the wetness that keeps smells going, and can attract flies that breed in water pools.
Think ahead, and store up autumn leaves in a dry place, to use in your composting operations going forward.
Get the mix right, and your heap will heat up to produce dark compost in a matter of weeks, if you turn it over every couple of weeks. Just moist, not wet, greens and plenty of browns.
Just a little effort does pay off. Your compost will be a stable dark material, ready to mulch over borders and shrubs to increase organic matter in the soil.
Treat yourself to a new, lightweight garden fork from Amazon. It will make turning the heap just that bit easier every time!
Smelly soggy compost, why does this happen?
Smelly soggy compost happens because there’s too much moisture in the mass of material that you want to turn into compost. Excess moisture, that can’t drain away, has the effect of sealing the compost. This stops air from getting in. You then get an anaerobic digestion which leads to a smelly soggy compost.
Think about forking in plenty of dry sawdust or dead leaves and straw.
Get it turned over and aerated and add dry ‘brown’ materials.
Then turn and add more dry browns every week or two.
This soggy material will then gradually turn into a drier, crumbly material that can be dug into the soil.
Follow the usual way of getting the green:brown ratio correct.
Approx 25 ‘carbon’;1 ‘nitrogen’.
In practice, this means a lot of dead dry brown material, with just a small amount of fresh green stuff, eg grass mowings.
Good way to store your dry autumn leaves is in a ‘pop-up’ bin. See the latest choice of lightweight storage on Amazon
See the other hints on this blog.
Smelly compost bin, why?
A smelly compost bin will happen when the contents are too wet and not enough air can get into the mass of material. You may wonder why this doesn’t correct itself naturally. Given time it probably would but the intervention of digging over the compost bin and adding dry ‘browns’ will remove the smell quicker.
It really does mean running several of these bins, if you have space.
Then, you can add loads of sawdust, or shredded newspaper to that wet foodwaste, as you load it into the bin, each time, to avoid smell from your compost bin.
Yes, you are adding bulk, but your yield of nice black compost will be much greater. I always need more compost than I can make, so I always try to find sawdust, straw, paper etc to use right through the year in my compost.
That is the best way to have a smell-free compost bin.
Compost smell on hands.
What can I do about the stinky compost smell that has got onto my hands?
This can be a real problem if you have just washed your hands, and, as they warm up indoors, there is a really bad sour smell of rot on them.
The stink is, usually, butyric acid based, but can be from a number of compounds generated in a foul-smelling compost heap that is wet and soggy.
Being anaerobic, a wet and soggy compost heap, will be partly fermenting these stinky organic acids, and, partly, producing sulphurous compounds through various chemical and biological processes, some, caused by bacteria that like these rancid conditions.
There will be free sugars (water-soluble sugary juices from discarded fruit), that bacteria will metabolise (use as a food source) very quickly. Their by-products can be very smelly indeed, and really make your hands smell terrible, even after thorough washing.
Of course, you would have worn rubber gloves if you had known how bad and persistent these smells were!
Anyway, here you are, having washed in warm water and soap, about four times, and it is still there!
This is what you do;
Make sure you check for any fresh cuts in the skin of your hands or any other exposed area.
If you do have a cut, get a suitable disinfectant solution in a plastic bowl, and soak your hands in the solution for a good five minutes. (Follow mixing instructions on the disinfectant container label)
If you use Dettol (which is a registered trademark product), this is a phenolic disinfectant, of a type that goes white when mixed with water, the smell of the disinfectant will begin to mask the compost smell.
Do not abrade your skin by hard brushing or scraping, or rinse off the disinfectant solution, just dry with a towel.
If done properly, compost smells sweet and ‘earthy’…so there are no problems with smelly juices getting onto your hands, getting engrained into your skin, and, hanging around for most of the day…just when you have to meet an important guest, or be at some other consequential event!
Most importantly, do not stop composting because of this bad smell experience.
It is well worth following this excellent video to get some really valuable black compost for the garden.
Soil organic matter is lost, by oxidation, every time we dig, hoe or disturb the soil in any way…so we do need to replace this with some dark compost whenever we can, every year if possible.
Can I use smelly compost?
Don’t use smelly compost. Do all the things that stop compost from smelling. This, simply, involves opening up the compost mass and mixing in dry ‘brown’ material to soak up excess moisture and allow air into the mix. After you’ve done this, your compost won’t smell and you will be able to use it.
Do not be tempted use smelly compost as a mulch around any valuable plants, or in a seedbed for small seeds of food plants for human consumption.
We all get it, occasionally, but what matters is, how you proceed from this point.
Avoid smells by using the correct mix of greens and browns, then aerate the heap by turning every few weeks.
Apart from the unpleasant smell, and tricky disposal operation, there is a loss of nutrients and other benefits that a good black crumbly compost would have given you.
It is definitely worth watching this video which gives many useful tips on making great compost.
Compost smells like garbage.
If your compost smells like garbage, this will mean that the mass of material is going through an anaerobic digestion phase, rather than a composting, decomposition phase. Anything that’s going through an anaerobic digestion will smell like garbage. This can be easily corrected by adding dry, ‘brown’ material to the compost.
The smell is similar to that of a street trash can that needs a good washout with sterilizer solution.
Garbage-smelling compost needs a lot more dry, dead leaves, sawdust, shredded cardboard or straw, plus turning over regularly.
How to stop kitchen compost bin from smelling.
The best way to stop a kitchen compost bin from smelling is to empty it regularly. Do this every other day and you should stop the smell. It will help if your kitchen compost bin has a carbon filter but it’s not wise to rely too much on it. A carbon filter will reduce the smell but it won’t stop it.
A kitchen bin, or caddy, can start smelling really badly after a few days. This is because of the warm temperatures in the kitchen.
There are several ways to stop it from smelling.
A quick wash and spray over with a fragrant cleaning fluid, after emptying, all helps.
Some people use bicarbonate of soda powder, sprinkled in the base, after washout.
It is not possible to get a completely odor free compost bin, or caddy, but we have found that torn up newspaper lining the caddy will soak up liquids which can begin to smell quickly.
One of the best smelly bin solutions is to empty it every day, of course.
Where this is not convenient, you can buy bin odour eliminator products, that mask the worst smells.
Replaceable activated carbon filters are, sometimes, built into the bin lid. These are excellent, but I would also use a scented disinfectant for washing out the bin regularly.
Kitchen bin fresheners and bin odour neutralisers can be toxic to pets, so, please read the labels before using them.
It is not really practical to have an airtight odor-proof bin and anyway, without some ventilation, the bin would almost certainly, start smelling even worse when opened up.
Household bleach should be used occasionally (after a thorough washout) and will kill off most of the offending bacteria on the bin surfaces.
The problem is, though, as soon as you load up the bin again, you are feeding the bacteria that arrive in the bin with the food waste.
This means you just can’t win by sterilising the bin with bleach every week. Even from a completely sterile bin, smells will arise very quickly when you start filling.
The compromise is the scented disinfectants and activated charcoal filters, as well as speedy emptying, every day or so, if you can. This is probably the best way to stop it from smelling.
The layer of torn up newspaper will keep things a lot drier, too. Without moisture, most bacteria cannot eat and breed.
A word about household bleach. Try to buy the basic hypochlorite bleach. This will be the best value, and will be strongest.
Be very careful not to splash into your eyes, both the concentrated bleach and the diluted solution you use to slosh around the bin. Flush with water immediately, and continue for 5 minutes. Get qualified medical assistance, if necessary, after flushing with water.
Always wear rubber gloves to prevent the bleach from damaging your skin. The bleach dissolves the fats in your skin, and can also be an extreme irritant if used regularly without gloves.
When using bleach solution for cleaning, the fresh smell of chlorine can be overpowering in a confined space, so use in well-ventilated areas,……outdoors is recommended!
Always read the label on the bleach container, and supervise minors if involved in the cleaning operation.