Composting Basics Part II: Hot, Cool, and Greens vs. Browns

If you read yesterday’s urban homestead boot camp post, Composting Basics Part I, you remember that I said I love compost.  Besides what it can do for you (you know turning “trash” into garden treasure, restoring and maintaining soil health, balance soil pH and neutralize chemicals, etc.), I love the way it does it.  I know it’s probably a little weird to love decomposition, but I do.

Yesterday, I told you that there are a lot of choices when it comes to bins, piles, and systems.  Worm bins and Bokashis are pretty specialized and self-contained systems.  I really don’t have much experience with either.   But I have used both a  pile and a bin.

A pile is best for “cool” composting.  It’s great if you aren’t in a rush for your finished compost, and if you don’t want to think much about it.  It doesn’t take a lot to build one.  And a pile probably won’t generate much heat, hence being “cool.”  Plan a year to two years for harvesting.  With this method, you basically just throw your kitchen scraps, yard waste and what-have-you into a big pile, and let it do its thing.  You can help it along by turning/stirring/forking it a couple of times a year, and by chopping up the browns you put into it.  Some people use a chipper or run over their browns with their lawn mowers before adding them to their piles.

You can cool compost in a bin too.  A bin will speed things up for you a bit more.  You will get more heat with a bin, and more heat means faster decomposition.

Right now, our family is “hot” composting.  A hot compost bin decomposes things very fast.  One pallet bin gave us over 80 gallons of finished compost in about 8 months last year.  For hot compost, you layer in your organic waste, give it a good soaking with the hose, and cover it (we use thick black plastic).  As it rots it generates heat, cooking the organic waste.  The heat actually comes from micro-organisms digesting everything. It can get hot enough to kill weed seeds.

The key here is you don’t want it to get too hot.  You want it to rot quickly and kill the bad stuff, but you don’t want to  kill off the good guys.  So you need to rotate it.  Or maybe aerate it is a good word.  Two bins make this nice as you can flip it from one bin to the other.  Sometimes, during the summer, we open it up, put out the half-finished compost, let the chickens scratch through it for a day or two and then scoop it all back in, water and cover again.  If you have a tumbler, there’s no need to use a pitch fork at all, just spin it.

So exactly what do you put in your compost bin?

“The greens” vs. “the browns.”  General advice is that for cool composting you need a 40/60 mix of the two, with more browns.  For hot composting, the ratio is even greater, closer to a 5 to 1 ratio or more of browns to greens. But what are they?

Greens include:

• fruits and vegetables, whole, pieces, peelings and scraps 
• moldy food
  
• chicken, rabbit, goat poop and other manure from herbivores
  
• alfalfa pellets
  
• coffee grounds and used tea leaves
• green leaves or grass clippings
• hair
• weeds (if they have mature seeds, make sure they are hot composted, otherwise not)
• algae and water from fish tanks
• urine

Browns include:

• egg shells
• dried leaves and grass clippings
• straw
• wood chips
• saw dust
• dryer lint
• paper, including shredded paper, newspaper, tissue and paper towels
• cardboard
• coffee filters and tea bags
• cotton fabric or string, wool
  
• cotton balls and swabs (the kind with cardboard sticks)
• any plant with woody stalks or stems, including corn cobs
• nut shells
• end of season plants
  

The greens provide nitrogen and the browns give carbon.  The only things I don’t compost are dog/cat poop, human feces, and bones.  All of them can be composted but they can make your pile smelly and attract animals to your pile.

The problem a lot of people have is that the ratios are talking about weight, not volume.  The browns are generally dry and weigh a lot less than the soggy wet greens, so you need a lot more of them.  I have to admit that I don’t really pay close attention to the exact ratios.  I tend to think of the greens as “wet” and the browns as “dry.”  Sort of like the browns are a sponge and the greens are the stuff I’m using to get the sponge wet with.  It’s totally simplistic, but it works somehow.  Even with the hot composting, I just think “Is there enough?  I better put more.”

There are all sorts of cute counter top containers for compost.  I keep a big stainless steel bowl on my counter to catch all of our kitchen scraps, our greens.  I used to use a porcelain one, but it got ruined, so stick with stainless steel.  When it is full or before bedtime, we take the bowl out to the pile.  I cover the bowl with a plate in the summer if fruit flies are a problem.

Most people don’t have a problem coming up with enough greens.  Browns can be tougher.  It helps to keep a source of browns nearby.  Yard waste is perfect.  We beg leaves off the neighbors in the fall.  In the summer, instead of putting grass clippings in as a green, we [have our neighbor who collects his] spread them around the chicken area.  The hens use them as littler and for a couple of weeks until they are completely dry.  Then we rake them up and toss them in the pile.  Dried leaves, straw, dead plants, wood shavings and shredded paper all work.  Usually, as long as you keep plastic out of it, the bathroom trash is all compost-able.

In addition to your greens and browns, you pile will need air and water.  Keep your pile moist – like a wrung out sponge, or chocolate cake.  We cover ours to keep the moisture in during the summer.  And we turn it and mix it.  It gets quite hot in the middle, so we move the middle to the outside edges and the edges in to the center to cook.  Then we water it some more and cover it back up.  Some people add soil or finished compost to their pile.  If your soil is healthy, it has all kinds of good micro organisms that help with decomposing your pile.  It’s sort of like adding yogurt to hot milk to make more yogurt.

What about the smell?  As long as you aren’t adding milk, meat or carnivore poop to your pile/bin, your compost should not smell foul at all.  If your pile has any odor other than a good soil smell, you probably need to turn it, add browns, or both.  Sometimes our bin gets an ammonia smell.  This usually happens after we’ve added the contents of the chicken coop to the pile and it’s had a chance to get going.  Chicken manure is very rich in nitrogen.  Adding in more browns and mixing it up, getting the inside to the outside and vice-versa, takes care of it.

When your compost is done, it should look like great soil.  No big bits or pieces of anything, light and fluffy, not soggy at all.  The compost shown above still has bits of egg shell and wood shavings (the browns take the longest to decompose) but I would put it in my garden like this anyway.

Happy composting!

Related articles

• Composting Basics Part I
• DIY Pallet Compost Bin
• Frugal Friday: Composting
• Pros and Cons of a Push-Reel Mower
• Remedial Composting