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Make Compost Fast - Hot Composting in 3 Weeks

3 Pallet Compost Piles

3 working hot compost piles

3 working hot compost piles

Why make compost?

I’ve been making my own compost for years. As we all know, it’s a long, slow process where we built up our waste materials in layers and leave it all to rot down, as it eventually will.

It was only this year, when the pandemic struck and left us all without access to the shops in the spring that I found I needed to make my own, fast.

I always start the Spring off with fresh bags of compost in which to grow those precious seeds that will give our gardens flowers or vegetables, or both.

With none available locally, I was lost.

Until I learned how to use the hot composting method to make compost in just 3 weeks.

This method works beautifully, and with the increased popularity of both raised bed and no-dig gardening, is a skill no gardener should be without.

Fast Composting for people who can’t be bothered reading the whole article

What you need:

  • mix of green and browns, all of which has been shredded or otherwise reduced in size
  • water
  • oxygen (air)

Mix into a big pile that is at least 3’ x 3’. Turn weekly for 3 weeks, adding water and air each time.

Browns and Greens

You’ll have heard about browns and greens if you’ve ever tried composting. The ’browns’ are the carbons, the ’greens’ are the nitrogen, and we need both to make compost.

We also need air and water.

Before we get to that, we need to drill down into the actual ratio needs of the brown and greens.

It is generally accepted that we need 6 times as many browns as greens, but that’s not as simple of just dividing up your material into piles and thinking one pile is all carbon, and the other pile is all green.

All your piles will have a mixture of carbon and nitrogen. Cut grass isn’t all nitrogen, just as brown leaves aren’t all carbon.

Sometimes we can be blinded by science, but there really is no need, just aim for an pretty equal ratio and all will be fine.

A great way to mix brown and green is to mow your grass when it is covered in fallen leaves rather than sweep the leaves into piles.

Save your cardboard boxes, and when you have more greens than browns for your hot composting pile, simply rip up the cardboard using a shredder, else tear it into pieces and run your lawn mover over it to shred it.

I have a found a good office paper shredder will snip cardboard fairly easily into small pieces.

At a push, you can tear it up by hand and add it as layer to your compost pile.

Most kitchen waste is considered to be green, so you will want to mix it with browns, which is basically something that has been dead for a while, like old grass that was cut weeks ago, or leaves, cardboard or shredded paper.

My first hot compost pile

Compost pile covered with old wool carpet

Compost pile covered with old wool carpet

List of browns and greens

BrownsGreens

Dead leaves

Grass clippings

Straw

Chicken manure

Dried grass

Horse manure

Cardboard

Freshly cut branches

Newspaper

Hedge clippings

Nut shells

Coffee grounds

Charcoal

Urine

Wood ash

Seaweed

Dried branches

Vegetable peelings

Chop up your waste material for a quicker process

For fast composting, you really need to give nature a helping hand.

You can easily do this by carefully preparing your waste material to make it as small as possible.

This means

  • Shredding your leaves
  • Shredding your branches
  • Crushing your egg-shells. I do this by leaving them in a low oven for half an hour to dry them out, then inserting into a plastic bag and running them over with a baking pin to crush them to almost a powder
  • Ripping open your used tea bags. Most of them won’t compost anyway because they are sealed with plastics, but you can easily pick them out afterwards
  • Chop your vegetable peelings finely, else add them to a blender before putting them on to the compost pile
  • shred your paper and cardboard waste

How to hot compost - fast

You could have a compost pile in your garden already, or several, but now is the time to get it to work, fast.

This method works so fast, you really need to ensure you have plenty material to hand.

I built a pallet compost pile, but when it filled it up and was nearly ready, I had to start a second pile nearby and I had no pallets left, so I just made a pile.

Layer the pile. Add a layer of sticks, if you have them to hand. Ideally, you want to put the most spaced out material at the bottom. This encourages air entry.

Then add grass clippings if you have them, maybe just enough to completely cover the sticks.

Add water. Even if what you adding is a ‘green’, which already has moisture in, add water anyway.

Add all your materials in layers. Leaves, grass clippings, hedge trimmings, kitchen waste (I like to leave kitchen waste in the middle somewhere), shredded cardboard/paper, discarded weeds.

A lot of people don’t re-use their weeds in this way, but if you follow this guide, and keep the temperature above 130 degrees F for 7 consecutive days, you will kill off any weed seeds.

Keep adding water every couple of layers.

When your pile is at least 3’ by 3’ it is ready to hot compost. Smaller piles will struggle to heat up so please try and find enough material to reach this (minimum) requirement.

Hot Composting - the Magic Happens.

You’ve built your pile. It’s damp. Unless you live in a hot, dry country, walk away and leave it.

if you live in a hot/dry climate, you might want to cover it with a tarpaulin or plastic sheeting, to keep the moisture in.

I live in a vaguely warm (depending on time of year), wet climate and I covered my pile up initially but have since learned not to bother. My pile is in the most sheltered part of the garden where it neither dries out nor gets a soaking when it rains. It doesn’t need covered.

Within 24/48 hours your pile should start heating up. You can use a compost thermometer to check this, else just insert a metal garden implement into it, and feel the heat when you withdraw it.

Or you can just put your hand in, if you are feeling brave.

I say “brave” because you could get burned. It could get really hot.

Compost thermometers in two different piles (see top photo) showing very hot readings

Compost thermometer

Compost thermometer

Hot compost thermometer

Hot compost thermometer

Advantages of a compost thermometer

Buy a compost thermometer If you do not already have one.

Compost thermometers have a long probe to reach the centre of the pile, where it will be at its hottest.

You can guess how hot it is by putting your hand in (be careful, you could get burnt), else you can use any metal rod to check the heat.

Just place it deep into the heap, wait a few minutes, then withdraw it and check to see if it feels hot.

Compost thermometers take the guess-work out of it, giving you exact readings every time. You can leave it in situ and just glance at it as you walk past, or come to check your pile.

They are a must if you are composting weed seeds or diseased material. Many plant fungal or bacterial infections can be killed in a hot compost pile, if you can keep the temperature high enough.

For example, I have two mature sycamore trees that both suffer from maple leaf spot. This fungal infection is harmless to the tree, but unsightly to look at, as the leaves develop ugly brown spots in late summer that leads to premature leaf drop in early autumn.

While there is no treatment home growers can buy, we can help slow its spread by sweeping up the leaves in autumn and either burning or hot composting them.

To kill the fungus, the compost pile must reach 60°C/140°F for 7 days.

It is safer to use a compost thermometer than to guess your pile has reached this heat.

The process of fast composting

Depending on the composition of your pile, this high heat could stay for a whole 7 days, but most likely it will start to drop at some point before then.

Meanwhile, your heap will be rapidly losing height. And remember I said that it has to be 3’ x 3’ to work, so if was exactly that to start off with, it is going to have trouble maintaining heat once it contracts.

After a week, high heat or not, you want to turn it.

The purpose of turning it is to compost all the stuff on the extremities that never got the chance to be broken down by high temperatures, and also to re-introduce air and water into the pile, to hopefully kickstart the whole process. The heat will have dried out your material, so you really need to remember to add the water, in layers, like you did first time.

After just one week of hot composting, most of the contents are already well broken down and feel much lighter than they were when you added them.

it just takes ten minutes of your time and effort. During lockdown, I had all the time in the world.

Turn your compost pile into a new situation. I did it intially with a garden fork, but then I went online and bought a proper pitchfork.

What a difference that made! Unlike a fork, a pitchfork/manure fork actually wants to pick up compost.

Remember to add water for the layers, just like you did initially. Have your garden hose nearby.

Week 2, repeat the process.

By now, its probably struggling to heat up at all. It looks like compost but it feels too light to be compost.

Stay with the program. Give it that third week. All sorts of magic happens in that time.

I’ll be honest, the first time I completed this process, I was mildly disappointed.

The compost looked like compost, it acted like compost (plants will grow in it) but it didn’t feel like compost.

It felt too light. Yet this lightness is exactly why plants love compost. It is such an easy medium for them to grow in.

Get a pitch fork, sometimes called a manure or muck fork

Pitch fork

Pitch fork

Advantages of a manure fork

A pitchfork, or manure fork, is a boon for home coompost-makers. I used my garden fork initially this summer, and turning the hot compost pile was really hard work until I purchased the manure fork, which has more and longer tines, is lighter and is bigger than a garden fork.

It is lighter because it is not built for digging into hard ground like the fork is. It is the perfect design for lifting out manure or compost in the making, and cuts the work down considerably.

It’s my first ever pitchfork, and I’m wondering how I managed to garden all those years without one! It’s a fantastic gardening tool and an absolute must for hot composting.


Handy tips to keep your compost pile hot

Half-composted compost can be encouraged to heat up and complete the composting process by the addition of greens, at any later date

After my first attempt, which I used in a new high raised bed, I decided to attempt to keep the hot process going by adding to the pile while it was working.

I did that by adding thin layers of freshly-cut grass clippings to piles in their second or even third turn.

Like magic, they immediately heated right up.

Grass is mostly water and sugars. A chemical reaction takes place inside the sugar molecules an this is why it heats up so readily, and as it heats up it dries out, and converts to compost very quickly.

If you don’t have any grass clippings to add, add human urine. Like grass, it releases ammonia as it breaks down and the resulting compost is smell-free and safe to handle.

An alternative accelerant to use is coffee grounds which are also really high in nitrogen.



List of High Nitrogen Greens

  • Grass clippings
  • human urine
  • coffee grounds
  • horse, cow, chicken manure

How to make sure you have enough greens in winter.

Hot composting can be carried out at any time of the year.

You may find yourself short of greens in the winter months, unless you have access to the manure of farm animals, which, although brown in colour, is actually a green.

The waste of all herbivore animals can be used. The waste from carnivores like cats and dogs is best avoided.

If you know a local restauranteur or cafe-owner, you may find they will allow you to take their green kitchen waste for your hot-composting pile.

In summer, when greens are plentiful, it is a good idea to keep a supply pile ready for winter use. You can do this by simply piling them all together, grass clippings and all, and don’t add water. If you can flatten your pile to prevent air entry, all the better.

It will not break down, or if it does it will be very slowly. At any time in the winter, they will still be green enough for you set a fast-composting process in motion, while you have a plentiful supply of browns in the form of dead leaves.

You can even lay this compost pile in a bed inside your greenhouse, where, if you stamp it down a bit as well as water it well, it will slowly release heat and promote early plant growth. This is known as a hot-bed.

make-compost-fast

How to tell if your compost is ready

Sight.

Does it look like compost. Is it all a dark brown, or can you identify something you added in the process?

Smell.

Does it smell like earth or like rotten material?

Feel.

Does it feel like compost? Remember yours will be a lot lighter than shop-bought compost which cheekily contains tiny stones for added weight.

Where to build your hot compost pile

Ideally, you want your normal compost pile to be fairly near your back door so that you can easily add to it when you have kitchen waste etc to put on it.

A hot composting pile can be any distance away because you will not generally be adding to it during the process, unless you are quickly adding nitrogen to help it maintain heat.

Look for a place in your yard or garden that is generally unused, perhaps an area that is in permanent shade and so it unsuitable for plant-growing.

I positioned mine underneath a mature horse chestnut tree where even the grass resists growing.

it is a dry, sunless, and pretty useless spot that is just perfect for my hot composting piles.

What to do with your compost

If I need to use it straight away, I do.

It can be used to help fill a raised bed, or you can top dress garden soil to assist with your summer vegetation.

You can use it to fill flower pots or containers for plants.

You can top dress potted plants.

If any is left over, I simply leave it where it is. Earthworms will soon move in and finish off the composting process leaving you with beautifully rich compost the following spring.

Meanwhile, start your second pile with any bits from your first pile that hadn’t fully broken down.

What I did with my compost.

I filled a really deep raised bed that was 8’ x 4’ x 2’ deep. I put all dead branches in the bottom, then added layers of grass clippings and the content up two upright plastic compost bins I’d been adding to for 4 years, the contents of which were a slimey, smelly mess.

I added a couple of layers of forest leaves which had lain around all winter and were mostly broken down naturally. Then I added the contents of 2 compost piles, and topped it off with 2 bags of shop-bought compost as the shops were starting to to re-open by this time.

With the use of my compost thermometer, I soon learned I had actually built a hotbed as most of the (lower) contents had not fully broken down. It reached a low and steady 30°C/86°F and stayed at that temperature for weeks. The seeds and seedling I planted loved it. Over the summer the bed’s compost did lose about 6” in height as everything settled down but considering how tall the plants grew, that was a good thing.

The lush vegetation home compost encourages

make-compost-fast

Garden plants love compost

Home-made compost promotes faster and healthier growth of all plants. It feeds and protects those precious plant roots. Garden pests and diseases rarely survive going through a hot compost process, and almost never attack plants growing in it.

You can make it in just three weeks, and top-dressing your already growing plants will benefit enormously from all the protection and health-promotion offered by your compost.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Comments

Perspycaciious on March 20, 2021:

Fine article. I have made a large, circular one with garden fencing, black covering, and adding fertilizer, with alternating layers of soil, rabbits make fine fertilizer too. some chicken manure (if it is too fresh) might be too hot, so consult your county's extension service on that one.

GardenExpert999 (author) from Scotland on March 19, 2021:

Hi Peggy, yes me too. But it’s great to be able to make it quickly when you’re needing a lot of compost in a hurry.

Peggy Woods from Houston, Texas on March 19, 2021:

We have had a compost pile for many years. I don't turn it as often as I should, but we still end up with some great compost for our small garden.

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