Am I composting wrong?

Hello,

Just after some composting advice please, I built a compost bin and started putting stuff into it but have now realised that I need a second bin as we keep adding new stuff so never actually getting any compost.

I have an old plastic bin so will start adding to that and leave the first bin to compost.

My question is how do I know if I'm composting correctly, every time I open the lid it's soaking wet, is that how it's meant to be?

 

No is the simple answer what is the base made of? it appears to be standing on slabs on gravel. Mine stand straight on the soil and often too dry rather than too wet.
Also I would empty the contents of the plastic bags into the bin, the bags may well say compostable, but they do not really compost in home compost heaps at a significant rate, the compostable refers to a good hot commercial compost heap which is regularly turned and has a lot of material present.
I have two bins each about 1 cubic metre, one gets filled and then tipped into the other one and left for 6 -12 months. If I'm feeling lazy or busy I just empty the oldest one and start to refill it.

 

@GaGa73 - someone will be along before too long who is a better composting expert than me. However, some initial points.

Compost bins work better directly placed on soil so you encourage the ‘wildlife’ to do the composting work for you. You are aiming to get a good environment for red wriggly worms to set up home.

Stuff that goes in the bin should be a good mix of ‘greens’ and ‘browns’. Green waste is self explanatory but browns becomes a bit more complicated as it includes things like shredded paper. Having a good mix of materials helps the worms and bacteria get to work and the temperature within the heap will soon rise and assist the composting process.

You appear to be using it mainly for kitchen waste, which might be best in a bokashi bin. Start filling it with garden waste, especially a load of grass clippings to get the temperature up and you will notice a difference.

 

We do put plenty of garden waste into it, it's had loads of grass cuttings, leaves and even sawdust.

We do usually empty out the compostable bags but have just stopped recently while I figure out what to do, that's why there's whole bags in there now but not usually.

I do regularly put worms into it when I come across them in the veg patch.

So what do you think the reason is for it being wet? Should I add more sawdust and cardboard?

Thanks

 

@GaGa73 - I think one of the reasons it is wet is because it is on a paved surface. All composts make what is known as ‘compost tea’ which in an open bottomed bin just naturally drains away. Your bin looks very well constructed so I imagine nothing is draining away. Torn up cardboard, newspaper, etc. will help soak up some of the surplus moisture.

Ordinary garden worms are not suitable for compost bins - mostly they are red ones (fetida something or other from memory). You can wait for them to arrive naturally, buy them or get some from a composting friend.

Your bin looks quite large - I’ve been trying to estimate its size from the paving slabs. Could you put a removable division wall across the middle and split the bin into two halves. Filling half a bin more quickly might help also and then you can start filling the other half when side 1 is full.

 

Garden worms are different to the type you get in compost or wormeries.
Also, if you should get it to heat up it could kill the worms.

Mine never gets hot enough, but it all breaks down eventually.

You really need a lot more bulk in there is my thinking, more garden waste, it seems a bit like you are trying to achieve a halfway between a wormery and a compost heap.

I'll just add you have made a good job of making the bin.

 

You need airflow to make good compost. Perhaps drill 25mm holes along the upper edges. If it can be arranged, collect materials and make a compost heap/pile in layers of mixed materials. 70% green, 30% brown, moist but not wet. Insert broom handle sized holes in built heaps, 300mm apart.
There seems to be a minimum critical volume of a metre cube to get a good composting, certainly more is good. Try to achieve a transient temperature of up to60 deg C for 5 days, never more than 80 deg C (Less will decompose but not kill bacteria, seeds, spores etc.
I suspect your heap is wet due to condensation, ventilation could regulate this.

 

To help speed up composting, then you need a good blend of greens and browns. Also, the smaller the particle sizes in your bin will improve composting. Looking at your image inside the bin, the particle sizes seem to big with not enough browns, I would also empty the contents of the plastic bag and dispose the plastic separately, compostable plastic bags don't break down as quick as they say they do, trust me, my heaps can get up to 70c and above.

I make a soil conditioner using a small amount of horse manure, fresh used mushroom compost and wood fibre. I did use composted bark in the past but it is far to expensive now. hence using wood fibre as my carbon source.

The pictures below are from a couple of heaps in my polytunnel, one is only one week old the other 3 weeks old. The bottom two images is of a mix that is 6 weeks old and then passed through a 10mm mesh screen.

 

Apart from what's already been said, I think the kitchen waste is probably adding too much moisture without enough other material to soak it up.

 

I have 3 x 1 cubic metre wooden bins with lids standing on soil.
When bin 1 is full (which takes about 1 season) I turn the contents into the next bin and so on.

I do get a lot of cardboard from deliveries and I use as much of that as I can.
I save all tea leaves (I don't use T bags) veg peelings etc which goes into Waitrose Home Compostable Bags. I rip them and chuck them in too. The bags take about 1 year to completely disintegrate.
Lots of lawn clippings and all the stuff that goes through my shredder.
I don't compost any weeds that may have seeds as I don't turn the compost often enough to keep the heat up to kill them.

It's never wet and I sometimes ned to water it in the summer as it gets so dry being west facing.



Still a few twigy bits, but I'm happy to use it like that.

 

Wow, thanks for all of the advice guys

So I'll stop adding worms from the garden

Put a divider in the middle to create two bins inside

Drill a load of holes around the perimeter of the top timbers

Stop adding the "compostable" bags since they take far too long to decompose

Add more garden waste


Thanks again

 

For the best results your bin needs to be directly on top of the soil. You need all the "critters" to rise up and go about their business. This also helps with drainage too.

You are correct in saying that you will never get any proper compost if you are continually adding waste go it. This is what I do. I only add waste until about November and from November through to say April I store all my waste in a large sealed crate in my shed.

This gives time for all your waste that was in your compost bin to rot down sufficiently to become soil. Around April every year I completely dig out my compost bin. I take out crate after crate of well rotted down compost to top dress my plants.

When it's empty I take the waste I've been storing in the shed since November and throw that in, and start the cycle over again.

Mine doubles up as a wormery for my tropical fish and a great source of soil for my plants.

It's essential to keep it quite moist, especially in summer. A dry compost bin will send the essential critters back down into the soil where they came from.

 

Although a soil base is ideal, you can compost successfully on a paved surface. We have done in the past when we didn’t have an alternative. Our compost worked fine, it was a bit slow but whether this was the lack of a soil base or turning I’m not sure.

Adding lots of shredded paper as our brown helped speed up our compost here (on soil) and regular turning speeded it up again.

 

Composting on a commercial size will only happen on a concrete floor to avoid contamination. As we are talking about large heaps, they do heat up very quickly, hence why they need turned regularly. Otherwise the whole heap does not breakdown and will become stagnate in certain areas of the heap. Moisture within the heap due to sweating leaches to the bottom slowing composting as it becomes to wet further down and the same applies to the top as it has become to dry due to cooling down due to be done in the open air. If you can't turn the heap regularly then you need to get some oxygen in to heap lower down. Cooling at the top will not apply to those composting in bins, as it will be a sealed bin, but condensation can cause it to become to moist. The only thing that ruins composting on a commercial size outside is, water. Heavy rain can cause the heap to get to wet, which will result in the mix being ruined.

 

I don't have much to add really, but make sure your kitchen waste doesn't include meat/fish or cooked foods like bread - those are apparently the worst for attracting vermin. If you're covering the bin and it's still too wet, add something like waste paper or cardboard crumpled or roughly torn up and mixed in. I also put a few layers of flattened cardboard boxes on top before putting the lid on because I think it helps to keep the heat in. As they get wet/start to break down I tear them up and mix them in with the next batch of "greens".
Mine looks a lot like @Pete8 's pics at the same stages so I think I'm doing something right!