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HOW TO COMPOST

 

There are many, many ways to compost.  These include:

 

Decomposing over time

The managed heap

Bins  -  Continuous or Batch

Pits

Layers

Mulch

Anaerobic

Vermiculture

 

Decomposing

People who are afraid of compost don’t know how easy it can be.  You just take a look at what nature does, and do the same.

 

In nature, plants die and fall to the ground, leaves fall from the trees above, twigs and branches may break off, birds or animals eat fruit, nuts and leaves and drop bits on the ground.  Left entirely to its own devices, this pile of organic material slowly breaks down into a wonderful, crumbly, dark-brown, sweet smelling substance known as humus.

 

You can do exactly the same in a quiet corner of the garden.  Mostly shady is good, so that the heap doesn’t dry out too much.  Under a tree is not such a good idea, as the roots will grow up into the pile.  If under a tree is the only possible place, put down a barrier first.  This can be heavy plastic (I have used discarded plastic table-cloths or shower curtain liners), or a concrete slab if you are going to be composting in that spot for several years to come.

 

I used to think that concrete was a really bad idea as it would prevent the worms from getting into the compost.  However, I have discovered that those worms will cross 20-25 feet of asphalt to get to an active pile.  You can always give them a hand by dropping into the pile any worms that you disturb in other parts of the garden.

 

It is a good idea to spread out some twigs and small branches first, as this provides some aeration of the pile.  Then you drop on to your pile anything organic that comes your way.

 

About a year after you start the pile, you scrape off the top layers, which will not have broken down completely, and underneath you will find your first compost.  Shovel this directly on to your flower beds, or into buckets to take to other parts of the garden, to begin a new bed or to refresh existing ones.  The partially broken down stuff can either be used as mulch, or as the base layer of the next pile.

 

It’s that simple.

 

Some people begin their piles in spring, some in the fall.  There are good arguments in favor of both, but I think for the pile-it-up-and-leave-it type heap, I prefer the spring, mainly because that way your compost will be ready by the following spring when you start planting for the new season.

 

That said, there is no bad time to start a compost pile.  Just do it when you are ready.

The Managed Heap

This is the next stage up the composting evolutionary scale, and is really very little different, except that you will perhaps add food scraps from the kitchen.

 

There are many very pretty ceramic counter top containers into which you put your fruit peels, potato peels, stale bread etc, etc, until you can empty it into the compost bin and cover it with leaves or straw or shredded paper. Every four or five days is quite often enough.  I have a bucket under the kitchen sink, and although it does attract fruit flies, it does not smell, and I only empty it when it is full.  I also put an inch or two of completed compost at the bottom of the bucket, in the hopes of getting a head start on the composting process.

 

A managed heap is still a pile-it-up-and-leave-it type, but you take more care about what goes into it, and how it is maintained.

 

For example, if you add a lot of green material, you will try to balance that with brown.  If you find yourself with a lot of brown material, you will look for some green to activate it.

 

In addition, you may take steps to ensure that the pile is well-aerated, and has sufficient moisture.

 

You can keep the pile aerated by repeated turning, or by inserting “chimneys” in the form of perforated PVC pipes, or bundles of sticks, or a circle of chicken wire.  Sometimes it is necessary to add some bulking material such as straw or wood shavings to increase porosity.

 

Remembering that the bacteria can only absorb nutrients in solution, it comes as no surprise that the compost pile needs to be moist, with 40-60% water content.

 

Water content is best checked by a squeeze test.  If water seeps out between your fingers the pile is too wet.  If, when you open your hand, the material crumbles, it is too dry.

 

The only remedy for too much moisture is to turn the pile, incorporating some dry matter as you go.  You can prevent the problem by covering the pile in very rainy weather.  Just don’t put black plastic right on top, as this just makes the problem worse. The problem with too much water is not enough air and the plastic excludes air altogether.  I know because I did it.  So cover before it rains, but leave an air space, or remove the plastic as soon as the rain stops.

 

You can water a dry pile, but it is difficult to get the water through to all levels.  Again, turning the pile is the best solution, damping down each level as you go.  Or turn it in the rain!

 

Bins

Once you begin to manage your pile, you may find it more convenient to construct (or purchase) some kind of container, at which point your compost pile becomes a compost bin.

 

Homemade ones can be made from chicken wire, snow fencing, circles of hardware cloth, old wooden pallets, or wood and wire.

 

 

 

Two very simple bins.  If they are held together with clips, they can be easily opened up and moved to another part of the garden.

 

 

The so-called New Zealand bin, composed of two pairs of hinged wooden frames with mesh, latched together at the corners with hooks and eyes, allowing for very easy dismantling.

 

 

 

A similar bin can be made of sections of fencing, but old pallets work just as well.  They can be held together with wire at the corners, with the front being loose to allow access to the pile. 

 If you can find a fifth pallet that fits flat inside the other four, then you have a simple, yet effective aeration system.

 

  

A more substantial type of bin is this cinderblock bin. There are spaces between the blocks for aeration, and this bin can still be dismantled and moved if so desired.

 

For a more permanent version, the blocks can be cemented together.  In that case, I would suggest turning the blocks so that the holes are horizontal allowing for a good flow of air in and out of the pile.

 

On the market you can find a wide range of bins, usually made from black plastic (recycled I hope).  One I used with a very satisfactory outcome was the Geobin, which produced a useable batch of compost during the summer months. It is a length of stiff, perforated plastic that you form into a circle and anchor with stakes.  The stakes are the weakness of the system as they are too flimsy and not long enough, but they can easily be replaced by bamboo, fence posts or rebar.

 

All the above bins are so-called holding bins.  This means that you are still using the pile-it-up-and-leave-it or continuous method.  Material is added until the bin is full, and then you start the next one, and the process is slow.

 

I have five bins across the short end of my vegetable garden, made up of pallets tied to the fence with wire.  There are three active piles, with a space to turn them into, as needed, and the fifth bin is to stockpile leaves and/or straw.

 

I have aimed for hot piles several times in the past, but only achieved warm until I built my weed pile.

 

Continuous piles, that is ones which you add to bit by bit, are almost always cold or at best warm piles, in large part because you need a critical mass of about a cubic meter for a pile to heat up significantly.

 

But you can achieve a good hot pile with a little patience.  Think of the time it takes to build a large enough pile as a form of stockpiling.  Once you get to the desired volume, you turn the pile to mix all the ingredients together and add an inoculant.  A readily available and very effective medium is urine. (see What to Compost). It needs to be diluted, so fill a bucket four-fifths full and encourage the family to pee in it.

 

Other inoculants are bone, blood or fish meal, and (I’m told) dry dog food.  However, I think that going out to buy material for your compost heap is a little like cheating.  Compost should be made from what is available, and free.  There may be times when you have to resort to a commercial product because nothing else is available, but this route is really a last resort.

 

Check the temperature of the pile, which should rise to at least 130ºF, and turn it when the temperature falls noticeably, or when the temperature goes past 160ºF.  Eventually the temperature will not rise again after the last turning, but will remain at more or less ambient temperature. This means that bacterial activity has just about finished.  The pile now needs to sit for a while so that the fungi can have a go at the hard-to-digest carboniferous materials.

 

 

Batch (hot) Piles

To get a successful hot pile, you need :

  • At least 1 cubic yard of material

  • A C:N ratio of about 25:1

  • At least 50% moisture (optimally 55-60%)

  • Good air circulation

  • Good structure

 

The C:N ratio, air circulation and moisture content are the same for any type of managed pile. Size and structure are more important if you want to achieve a hot pile.

 

One cubic yard of material may not seem like a lot. But believe me it is.  I reckon that you need at least 44-50 five-gallon buckets full of material to get that much.  When the material is chopped quite small and well-watered, it literally weighs a ton.  Something to remember when the time comes to turn the pile!

 

There are times of the year when finding enough material to build a hot pile is not difficult.  For example, last July I got home after two weeks in France to find the garden was an absolute jungle.  Not only were there weeds everywhere, but also most plants had grown way beyond their most attractive size.  Something needed to be done.  I pulled weeds to fill 20 buckets.  I pruned and trimmed and cut back everything in sight.  Another 20 buckets.  Then a friend who doesn’t compost (yet) turned up with three garbage bags full of grass clippings and I was in business. The pile heated to about 135º and was done in about 6 weeks.

 

At other times of the year, particularly the spring, there is an abundance of brown material from leaves raked on to beds as winter mulch, and many twiggy bits from pruning out deadwood, and other clean-up activities.  But there is not much green – the grass is just beginning to grow, the weeds haven’t started yet.  Unless, that is, you have been invaded by garlic mustard. The young leaves can be added to salads, and make a very passable pesto.  But make sure that you pull the plants before they begin to flower (late April) and add them to the pile.  Another good spring source of green biomass for the compost is marsh marigold.  While it is a very attractive addition to the early spring garden, it can easily get out of hand and take over.

 

This is the time when you need a good source of manure.

 

Structure.  If the particles in the pile are too large, there are limited opportunities for the bacteria to get to work (remember the illustration).  Think of ice – a large chunk will melt very slowly, but crushed ice melts as you look at it.  This is because the crushed ice has a vastly greater surface area on which the warming forces can work.  So too, smaller particles in the heap provide a greater surface area to come into contact with air, water and bacteria, and it will break down more quickly.

 

You can reduce the size of particles in a number of ways – spread leaves out on the lawn and go over them with the mower; when cutting back perennials or pruning shrubs, take an extra few minutes to cut the prunings into pieces not more than three inches long; put all your weeds in a pile and attack them with a machete.  My husband was appalled when he saw mine and gasped, Where did you get it?  The Building Company.  My son would probably be equally appalled to know that I let his then 4-year-old son whack some weeds with a machete!   (this leads to a completely gratuitous aside on child rearing: I believe that it is very important to let small children try nearly everything. Under careful supervision, and with an ongoing safety commentary, the kid learns the correct way to use a potentially dangerous tool, but also that it is not that special or exciting.  My grandson has not asked to use the machete again).

 

And talking of whacking weeds, leaves in a garbage can can be reduced in size by means of a weed-whacker.  A leaf blower/vacuum does the job very nicely too.

 

However, the particles should not be too small, such as sawdust, because this will form a mat and there is no room for air between the particles.  Similarly grass clippings, wood ash and shredded paper tend to become too compact.  They need, therefore, to be well mixed with other coarser materials.

 

Many books will advise you to build your pile layer by layer – greens then browns, then greens and so on.  This is not ideal as the bacteria need both browns and greens at the same time.  Commercial compost enterprises will mix and shred all the material before it goes into the pile, leading to rapid decomposition at heats high enough to kill pathogens and seeds.

 

For the home garden, you can purchase some type of tumbling bin.  The bin will not chop or shred the material for you, but it will provide good mixing and aeration, leading to quite rapid decomposition.

For the record, I have not used one of these myself, and I have had mixed reports about their effectiveness.  They are not cheap, so I would suggest that you ask around to see who has one, and what they think of it before you make the investment.  Unless you are very pressed for space, and have a large amount of material that needs to be processed fast, I think that there are other, more effective, methods.

 

Pits

My older friends talk about how their fathers used to take kitchen scraps out into the garden and bury them.  Seems like a good idea to me, and a perfect way to feed large shrubs and bushes.  Dig a series of small holes around the bush as needed, fill with the compost-to-be and lightly top with the soil you removed.  It’s a bit like an intravenous drip or hormone patch, providing a long-term source of nutrients.

 

Our old friend Sir Albert used wide, shallow (about two feet deep) pits for his compost factory at Indore in India.  He had plenty of space and plenty of labor available and the compost was turned three times, just as if it had been above ground (which it was during the rainy season because the pits quickly filled with water).  However, I see pit composting best employed in the garden as a way to prepare extensive areas for planting without having to ferry large quantities of compost from some other part of the garden.

 

In other words, the compost is made in situ.  This needs good advance planning as you will need time to fill the pit, and time for the compost to develop, not to mention the time that it takes to dig it!  However, once the pit has been dug, and most likely, tons of stones and rocks carted away, the work is done.  Spread your organic matter over the bottom of the pit, sprinkle on a thin layer of the soil you have removed and continue until the pit is filled, and then some, to allow for a reduction in volume as the matter is decomposed.

 

How long it needs to sit depends on what went into the pit, what the ambient temperature is, and the moisture content.  Stick your trowel in every so often and examine the contents.  When you can no longer identify the original ingredients, and it is beginning to look crumbly, wait another month to six weeks before planting.

 

 

Layer composting.

New bed preparation can also be done in the reverse order: build a pile over the entire area, and leave for about six months.  THEN you do the digging, or use a rototiller to incorporate the new compost into the old soil.  Again, let it sit for a few weeks to mature.

 

Begin with a layer of cardboard or newspapers, thick enough to suppress any weeds or grass in your chosen location.  Cover this with a layer of woody material – small branches, twigs, shrub trimmings – which allows some air to circulate.

 

Next pile on the weeds and whatever else you have available.  Then cover with leaves and a layer of soil, wood chips or compost to keep them in place

 

If this is started in the fall, the area should be ready for planting by late spring.

 

Mulch

Another way to get organic material into the soil is to use mulch, which has the added advantages of regulating soil temperature, maintaining moisture in the soil and suppressing weeds.  There are many materials to choose from: all types of bark, buckwheat, cocoa or peanut hulls, coffee grounds, hay or straw, hops, leaf mold, pine needles, ground cork or corncobs, wood chips, and of course, compost.

You will need to take into consideration availability, cost and appearance.  If your municipality collects and processes leaves and brush, you have a great source of mulch – usually free, and local.  If not, here is an opportunity to get such a process started.

 

Anaerobic composting. 

What composters try to do is incorporate air into the pile or bin so that the aerobic bacteria can do their work.  We try hard to avoid anaerobic conditions because, although these will also eventually lead to fine compost, the process is nearly always smelly and unpleasant.

 

Anaerobic composting does, however, have a place, particularly during the winter months when the aerobic bacteria take a vacation.

 

If you keep a large plastic bag or plastic trash can near the kitchen door, you can empty your kitchen scraps into it all winter long. Just make sure that you also add a thin layer of soil with each deposit. And make sure that there is sufficient moisture (anaerobic bacteria need as much as 70% moisture) and that high nitrogen materials are present.

 

When the bag is full, it is then sealed and left alone for several months, in a spot that gets some sun. The compost is finished when the odor is earthy. If unpleasant odors persist, more time is needed.

 

 

 

 

 

Vermiculture

 

Vermiculture, or using worms to facilitate the compost process can be as simple as a bin with shredded paper in the kitchen or classroom, or as elaborate as a farm like Worm Power in Avon, NY, where over 8 million worms consume prepared manure and silage to produce what is recognized as the best long-term natural fertilizer available: worm poop, more formally known as worm castings.

 

Compost worms (Eisenia foetida or Lumbricus rubellus) need moisture, air, darkness and modest warmth.  And, of course, food. They are somewhat picky eaters so you cannot just throw in anything as you can with a compost pile.  They don’t care for oils and fats, nor very acidic food like citrus rinds.  But give them a daily diet of fruit and vegetable scraps and they will be as happy as can be.  They consume about half their own weight a day, so if you started with a pound of worms, you can add half a pound of scraps each day, adjusting up or down according to how fast the material is consumed.  Finely chopped or even blended scraps will go much faster than large chunks.

 

The worm box can be plastic, wooden (lined with a plastic bag or old shower curtain) or glass (like an unused aquarium).  There should be a loose-fitting lid which allows air into the box.  Bedding can be shredded paper or chopped up leaves.  Worms love leaves, but they don’t really hold moisture and are best mixed with paper of shredded cardboard.

 

Eventually (about 4 months) there will be mostly castings and very little bedding.  At that point you need to harvest the bin. One method is to push the contents of the bin to one side, add fresh bedding to the empty side and put food scraps only on that side.  The worms will soon migrate towards the food, especially if only the new side is covered providing the darkness they crave. Now the compost can be removed from the old side and fresh bedding added there as well.

 

Another method is to dump the entire contents of the bin on to a sheet of plastic or paper.  Form several cone-shaped piles.  The worms will move towards the bottom of the pile to avoid the light and the compost can be removed from the top. There will still be some undecomposed scraps and some bedding.  These can be separated out and returned to the bin.  Repeat as the worms move further down.  When they can’t go any further, return them to the bin with fresh bedding, and you are set for another few months.

 

I have to admit that I cannot really be considered an expert of worm bins as I managed to kill off my worms in just a few months.

 

 

Ways to make compost are legion – and in the long run it all works.  So, I encourage you to start if you haven’t yet and to continue if you have.  Remember to practice Organismic gardening – keep those micro-organisms happy and they will reward you with a product that improves the health of your garden.