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Composting
Introduction
to innovations in composting
Disadvantages of plastic composters
Disadvantages of traditional wooden composters
A new, improved design for the wooden composter
How this design overcomes the disadvantages of the
traditional wooden composter
Other methods of supporting the boards in this design
The 'low-level composter'
Turning the heap
The 'Greenhouse Composter'
The practicalities of making
moveable boards
References
Restrictions and advantages of the restrictions
Introduction to these innovations
The innovations in composting can save a very great deal of time, money and effort - and by 'saving effort' I mean eliminating backbreaking work as well as moderate effort. First, in the section on composting, I use some concrete situations to bring out the differences between two composting systems, or methods. I show, I hope, that improvements can be made to existing ways of using a compost bin, constructing a compost bin and buying a compost bin. In later sections, there's a more systematic and detailed look at the drawbacks of existing composters and the benefits of my new system, complete with photos and diagrams. I introduce this composting system in different ways, then. Unavoidably, there's some duplication of information.
The new system is for people who don't have unlimited time, who recognize the importance of composting but who have many other interests and responsibilities, for people who want to go beyond 'beginner's composting,' using a single small bin, which is inflexible and can't deal with the large quantities of material which are sometimes available, and, I hope, for people who are very experienced in composting.
The two methods are:
Method 1. methods of producing compost in existing compost bins, methods which are generally inefficient and in need of improvement, I claim.
Method 2. the improved methods I suggest, based on the use of boards, supported on metal or wooden stakes inserted into the soil. The boards which make up the sides of the composter are self-supporting and can easily be moved to a new part of the garden or allotment. The system allows the compost bin to be easily taken to the materials to be composted, rather than taking the materials to the compost bin. This will often save a great deal of time and effort. Alternatively, the compost bin can be sited in the usual way, in a fixed position. The boards can be used to make modular units of very different volumes and to make different numbers of modular units, giving a system which has complete flexibility. Except for the boards used in the 'standard composter,' the boards are low, allowing materials to be pitched into the bin directly from a wheelbarrow at any time - a massive advantage. New boards and new units can be made in a fraction of the time needed to make existing compost bins and gardeners who prefer to buy their compost bins need only buy three boards, or just two, for some applications.
The edging for beds, including raised beds is also made up of boards - gravel boards or planks - which are supported by a metal or wooden stake so that the edging board is self-supporting and can be moved very easily, allowing the boards to have more than one function and giving other advantages.
The two boards which form the basis of the system I've devised are:
In describing the uses of this composting system, you may well think that I'm giving unnecessary detail. The fact is that in ergonomic studies, in studies of efficient working, it's necessary to break down the task into separate stages and to concentrate attention upon each stage. Only by doing this can we see any inefficiencies of the overall process and eliminate the unnecessary stages.
First
situation: composting nettles
Nettles, of course, are very valuable materials for the compost heap, containing
a good quantity of nitrogen, readily usable by the bacteria which start off
the composting process. Nettles are almost as useful as comfrey. Let's assume
here that we're lucky enough to have a large nettle patch.
Method 1. We cut the nettles, using shears, a strimmer or a scythe, or else we pull them out. Even the use of a strimmer isn't effortless. To state the obvious, the strimmer has to be carried from somewhere, and they aren't always straightforward in use. Whatever method we've used to cut them, we wait until the nettles have wilted, or we wear gloves and transfer them immediately to the wheelbarrow. We take the wheelbarrow over to the compost bin and lift up the nettles to place them in the bin. We can't lift up all the nettles in the wheelbarrow at once, so we have to do it in separate stages. Then we go back to the nettle patch repeatedly for further wheelbarrow loads until we've cleared the patch. A great volume of nettles will be needed to make a useful quantity of compost. The work may not be too hard, but it will take us quite a long time. We add other materials to the nettles in the compost bin to create a fairly well balanced mix. All these additional materials need to be lifted up (more tiring work, of course) in order to put them in the composter.
Method 2
We take light boards, such as the Grange edging boards I discuss later, over to the nettle patch and push the stakes into the ground, a matter of moments. We've surrounded the nettle patch to make one single rectangular unit, then. We add other materials to the nettles, which are growing inside the composter at the moment but which will soon begin to break down, if temperatures are suitable. There's no need to do the work of lifting up these other materials to put them in the composter. If we use Grange edging boards, then we can just tip the materials directly from the wheelbarrow on to the nettles. If we use higher boards, then each board can be removed so easily that again we can tip the materials out of the wheelbarrow without lifting them, until the material in the composter reaches a certain height. Of course, a conventional plastic compost bin is light enough to take over to the nettle patch, but it will only enclose a very small area. Using the modular system, we can easily enclose much larger areas.
Second
situation: composting a large quantity of hedge clippings
(Let's assume that the hedge, a long one, isn't overgrown, with thick stems.
It isn't years since the hedge was last trimmed and the stems are smaller
than the diameter of a pencil, and these will compost well. So, we've got
a great quantity of compostable material, and we don't want it to go to waste.)
This situation is very similar to the first, but now I give alternative courses
of action.
Method 1. We gather all the clippings from the full length of the hedge and form a large heap. Next, we fill the wheelbarrow and wheel it over to wherever the compost bin happens to be, a short or long distance. Then, we use a fork or our hands to lift up the hedge cuttings in the wheelbarrow and feed them into the compost bin. These are heavier than the nettles and the work is harder. We repeat the process for the remaining wheelbarrow loads. At the end of the composting process, when we're about to use the valuable compost, then we have to transfer the compost to the wheelbarrow - again, it's the lifting from ground level which makes the work so hard - and take the wheelbarrow to the bed where we'll be growing the plants.
Method 1. We decide whether we'd like to save work at the stage of putting the material into the composter, before composting, or at the stage of taking the materials to the bed, after composting. If the first, we form a large heap, place the boards in position and add other materials. If the second, then we take the boards over to the growing bed, place it inside the bed and bring over the hedge clippings and other materials (if the low-level boards are used, there's no lifting needed at all). When the composting process is finished, we simply remove the boards and spread the compost on the bed. We have to move the compost a distance of a few metres at most, and without any lifting - the movement is horizontal.
Third situation: we want to make a composter from reclaimed timber, or bought timber
Method 1. All the wooden composters needed for this method require some sort of supporting framework. Making the composter requires skill and takes an appreciable time.
Method 2. The wooden composters which are used in Method 2 don't need a framework at all, and by dispensing with it, we can save time and effort. Method 2 makes use of self-supporting simple boards supported by stakes. We can make the boards for this system in many different ways, and then simply screw metal stakes onto them, a matter of a few minutes. We can saw a reclaimed door in half to make two boards, we can use a whole door to make one large board, we can simply nail strips of wood of the same length to wooden stakes to make boards complete with supports, we can buy manufactured board in a weather-resistant grade which is cut to size and nail it to wooden stakes. There are many other possibilities.
Fourth situation: we don't want to make a composter, we want to buy a composter. The composter will be placed against a wall, or against the corner of two walls.
Method 1
Existing wooden composters for sale are bulky and heavy and have four sides. They can't be transported completely easily, either from the shop to the house or from the house to the garden or allotment. If the composter is going to be placed against a wall, then one of the sides is unnecessary. If it's going to be placed in a corner of two walls, or next to an existing composter and a wall, then two of the sides are unnecessary.
Method 2
The boards can be bought separately. Each board can be taken home separately, by public transport if necessary, and taken from there to the garden or allotment very easily. It's only necessary to buy the boards which are needed, perhaps only two. I focus attention here on Grange edging boards, which are very widely available, are cheap and which can be used to make an almost instant composter. Other, purpose-made, boards could be made available commercially very easily.
Introduction to these innovations in composting (all of this will be familiar to experienced users of composters.)
Vast amounts of organic material - household refuse, hedge clippings, grass cuttings and other garden waste - could be used to improve soil fertility but instead are diverted to landfill sites and contribute to pollution. For this reason, a large number of councils in this country make available subsidized compost bins. Some recycling has problematic aspects - recycling paper, plastic, glass, metals of different kinds uses energy and unavoidably produces some pollution. In very many cases, the benefits far outweigh any disadvantages but recycling may have only marginal benefits, or even none at all (as when a consumer drives some distance to a collection point to recycle a small quantity of paper.)
Of major recycling activities - of materials, rather than objects, finding new uses for objects - only composting can easily be carried out at home, or at the allotment garden. The benefits of composting are not marginal. They completely outweigh any disadvantages - unless, that is, a composter is used which involves the use of non-renewable or energy-intensive resources. People who begin to compost materials generally find it an absorbing and very satisfying activity. The compost produced is very valuable, providing balanced nutrients and benefitting soil texture. For these reasons, composting is regarded as a central activity in organic gardening and horticulture.
Gardeners can dispense with a compost bin and simply make a heap, but this is unsightly and uninsulated. Getting a heap to heat up isn't easy, but it's desirable if possible, so as to kill weed seeds. An uninsulated bin makes it more difficult. 'Cool - or slow - composting,' has some advantages (it's simpler and materials can be added when available, at intervals) but of course 'cool composting' too takes place more quickly in a well-insulated compost bin. It's far better to use a compost bin, then. These are made either of plastic or wood.
Disadvantages of plastic composters
Plastic is generally the best material to use for a water butt - making a watertight wooden container isn't an easy matter - but not at all the best material to use for a compost bin, even when the plastic is recycled. There are various objections to the use of plastic compost bins:
I used a Rotol plastic composter for a time, many years ago. It can produce very good compost and the design has undeniable appeal - a conical shape which looks very good. For all that, the Rotol has the disadvantages of other plastic composters. The top diameter is 45cm and through this fairly small opening all the compostable material has to be inserted (after being lifted up to a height of around 75cm.) The Rotol composter is made of unrecycled plastic.
Composters, then, if at all possible, should be made from a renewable resource, wood, and if it can be obtained, reclaimed wood.
Some disadvantages of traditional wooden composters
Even though wood is the best material to use for a composter, the traditional wooden bin has disadvantages:
A new, improved design for the wooden composter (the 'standard PHD Composter')
In the compost design I give here, each board is raised from the ground by the use of supports, which are pointed, allowing them to be pushed easily into the ground. Each board is self-supporting, but can be given additional support if required by very simple means. Boards can be moved easily, giving great flexibility to the user. If the composter is placed against a wall, then only three boards have to be used, if the composter is placed in a corner, only two.
The supports used in my original design are metal log roll stakes of 46cm length manufactured by Gardman, which work very well. They are cheap (packs of three cost me 2.98 recently), galvanized and will last indefinitely. Gardman stakes have three holes for attachment to the wood with screws.
Each of the four sides of the composter (or three sides, if the back is omitted) is self-supporting. This is one of the self-supporting sides of a composter, made from reclaimed timber, showing the Gardman metal stakes which support the timber, lifting it above soil level. The board is substantial and heavy, so three stakes rather than two are used, but they are perfectly able to support the board.
In tent design, I think it's far preferable to have a self-supporting tent rather than one which collapses without guy-ropes. Guy-ropes can be added to a self-supporting tent to withstand severe winds. One strut can be added to each unit of the composter to increase stability and to withstand strong winds, or else small loops or brackets can be attached.
How this design overcomes the disadvantages of the traditional wooden composter
This particular composter isn't, of course, a thing of beauty. I made it quickly from old reclaimed timber, which came from two compost bins of traditional design. but it isn't at all out of place in the allotment site where it's used and above all it's functional. Later, when the wood has dried out, a wood preservative in a suitable shade can be applied. The wood looks unsightly, particularly at the lower right hand side, because in its previous use as part of the traditional composter the wood was in contact with the soil and has absorbed water. The metal supports keep the wood away from the ground so that from now on it will rot far more slowly.
The system is flexible. The front board can be extended if wished, the board at the right can be moved in either direction to change the number of partitions or the size of the partitions. The composter is placed against the insulating stone wall, so that a back board isn't required. For beautiful gardens, a much more visually attractive composter of the same design can easily be constructed. If anyone acquires reclaimed boards of varnished walnut, then they are welcome to use them.
The straw in the composter shown above insulates the compost heap but can be covered with a sheet of polythene to keep the straw from becoming wet. Wet materials, of course, lose much of their insulating value, which is why the wet pieces of carpet which adorn so many compost heaps are next to useless as practical insulators. In fact, I use a multi-layer covering for my composters. The covering fits the top of the compost bin exactly and is far cheaper than the 'compost duvet' in the Organic Gardening Catalogue which costs 17.95 (!) and which is described as 'ideal for any square container', but will only fit a bin which is about 850 x 850mm - any greater and heat will be lost at a high rate around the edges.
For composting smaller volumes of material at intervals, dividing boards
can be used to make two, three, or more, units of the same size. Or there
may be one large partition and one smaller partition, as below. The larger
partition may contain a large volume of material obtained over a short time
period, which will heat up. The smaller partition may contain materials
added at intervals, to form a 'cool' heap.
If the composter can be placed against a wall, then there is only the need
to make (or buy) left and right boards, internal partition boards (one in
the example above) and a front board. The back is omitted. This makes full
use of the wall’s insulating value. If the bin is placed in the corner
of two walls there's only the need to make (or buy) two boards. On sloping
ground, all the sides of the composter can easily be made vertical, overcoming
the admittedly minor disadvantage of the traditional composter's leaning
sides.
4. The boards (2, 3 or 4) can be bought and transported separately, once
this design is made available commercially. Far more importantly, these
boards are not screwed or nailed to a framework, so that taking the compost
bin to a new location doesn't involve the inconvenience of taking the bin
to pieces again or moving the whole heavy, unwieldy object. Each board can
be removed in a moment, taken to the new location and pushed into place.
Other methods of supporting the boards
I used Gardman stakes to support the boards because I'd been using them to support the planks used in making the edging for beds. There are other means, for example.
Metposts 75 x 750mm. These are used for supporting the posts for fencing but can equally well be used to support posts which are fastened to large, heavy boards, such as complete reclaimed doors, used on their sides - doors saw in half are of a useful size, and can be used with other methods of support. (If we're concerned about appearance, we can avoid doors which have letter boxes and cat flaps.) In this case, the boards are movable, but only with a great deal of effort. Lifting machinery would be required to move the boards easily, so this system is better suited to use in organic horticulture or farming rather than organic gardening. However, a car jack, very easily obtainable, of course, qualifies as lifting machinery and with a little time and effort can be used to lift the boards. Smaller Metposts can also be used to support lighter but still substantial boards.
Wooden garden stakes with sharpened ends, available in many sizes. Lengths of wood can be fixed to two of these stakes to make a complete board. Home-made stakes can also be used. Or home-made stakes.
The most convenient way of making a low-level composter is with Grange edging boards. The capacity of the bin is much greater than would be expected. If the material inside is level with the top of the wood, the composter holds 315 litres, but more if the material is heaped up. The material inside will subside later. Many manufactured composters hold only about 200 litres. The cost of four edging boards is roughly 25.00, correspondingly less if two or three are bought. This compares favourably with the plastic composters in the 'Organic Gardening Catalogue' which cost 59.95 and 43.95 but have less capacity, or with the wooden compost bin which holds 600 litres but costs 85.75. This composter is put together in a matter of moments and other units can be added just as easily.
This low-level composter has the advantage that it's just the right height to allow the contents of a wheelbarrow to be tipped into the composting area, and from any available side. However, the higher sides of the standard composter can be removed so quickly that wheelbarrow loads can be added perfectly easily, until the compostable material reaches a certain height.
I tipped into this composter a sizeable quantity of bulky, heavy organic materials before I covered them with straw, and saved myself a great deal of work, the work which is unavoidable if material has to be lifted up to the opening of a plastic composter, or of a standard, high composter. (An empty plastic composter, if it has no floor, can be moved and placed over a small quantity of material, but after that, the material has to be lifted.)
The Centre for Alternative Technology factsheet on Cool Composting states that in composting, 'better results are obtained with containers that are:
This low composter qualifies on all three grounds.
The Centre for Alternative Technology's Factsheet is completely realistic in stating that very few people turn the compost heap, even if they have gone to the trouble of forming a heap which has heated in the first place. The heap is turned - if at all - after the temperature has reached a maximum and has then begun to fall. This is because moving such a heavy load deters almost all but physically strong and very committed people. The method I suggest eliminates most of the work. It may not be quite as effective as turning, but it redistributes the material, loosens the texture and introduces air spaces, so that the microorganisms can resume their activity and produce a second heating effect.
If a traditional wooden bin is used, then only the front can be moved or removed (labelled 'c' in the diagram below.) The very bulky and heavy material has to be moved out of the confined space, turned and then moved back again to its original position, as shown by the arrows. 'Moved' doesn't do justice to what is usually a back-breaking activity.
If a plastic composter is used, then the work becomes ridiculous. In many designs, there's a small opening at the base from which we're supposed to extract the compost (unfinished compost in this case, compost which needs turning.) Then, after turning the material, we're supposed to lift it all up and put it back into the opening at the top - and this opening is again too small for convenience. A design without a base - for example the Rotol composter - can simply be lifted up before the materials are turned, but it's unlikely that the composter can simply be put back over the materials. Again, some material will have to be lifted up and put into the opening at the top.
We simply remove the boards, move the material a short distance, which will introduce air spaces, doing some forking if we can - in this case, the procedure will be just as effective as traditional turning - and then surround the material with the original boards in the new location. The crucial saving in effort is due to the fact that we are simply moving material once, not moving it and then moving it back again - a 50% reduction in effort. Alternatively, we remove the boards so that we have unrestricted access to the material, do the necessary forking and then put the boards back in their original positions.
The PHD 'Greenhouse composter'
It occurred to me that the 'greenhouse effect,' which of course increases temperatures in a greenhouse, and, worryingly, in the world as a whole, could be used too to increase the temperature inside a composter and so speed up compost production, and to extend the composting season, so that compost is produced during most of the year. Any of the composters shown on this page can be given a transparent or translucent roof. This composter is identical to the PHD cold frame, so it isn't illustrated here. To see it, please click here. The one structure has two very different uses.
The practicalities of making moveable boards
If Gardman metal stakes are used to support the boards and the stakes are simply fixed to the board with screws, then the screws will almost certainly work loose before long. The secure fixing method I use is a little more elaborate, but not very much, and it's quick to implement. It solves the problem.
For an excellent contemporary treatment of 'cool composting' and of composting in general, please see Peter Harper's 'Cool composting: a fresh approach' a factsheet published by the Centre for Alternative Technology - an organization that is as important as HDRA, although of course its focus is different, and wider. The publication takes a realistic view of composting, recognizing that 'hot composting' isn't the only composting technique. The factsheet describes classical hot composting as 'the pursuit of perfection:' 'Unfortunately (quite apart from the effort involved, which is considerable) it does not really fit the patterns of modern life. In order to achieve heating a heap needs to be above a critical size ... and has to be constructed all at once. But it is unusual to have large quantities of both [the two types of compostable materials] available at the same time: both gardens and households tend to generate small amounts of both continually, with occasional gluts of one or the other...as for heating, it is not vital; very few people achieve it anyway, and its supposed benefits are simply not worth the extra trouble. And what's the hurry? ...Remember we are trying to minimize waste by composting, not produce 'perfect' compost at any cost.' However, what are described as the 'supposed' benefits of heating are real enough, as the fact sheet acknowledges: 'The heating kills most of the weeds seeds and pathogens in the raw material.' (Page 3.) The method I give for turning above should make it far easier to achieve the heating effect, if, that is, there's sufficient material available of the right kind for heating to be possible at all.
I'm in full agreement, of course, with the statement, 'It is surprising that there is so little systematic research on home composting. It seems to be generally assumed that everything that can be done has been, and that the only choices are from among existing methods.' (Page 5.)
Restrictions and advantages of the restrictions
The main restriction is that I don't deal here with large-scale composting, the composting systems needed if compost is to be sold, the composting systems subject to legislation, the composting systems which require an energy input (such as the composting systems produced by Accelerated Compost Ltd) with in-vessel composting systems in general.
The advantages of the restrictions? The advantages of composting in the garden or allotment, rather than sending the material to an in-vessel composting system, are very substantial ones. Compostable materials are mainly water, and transporting heavy masses of water - along with the valuable organic matter - may make economic and environmental sense, or it may not. Not if the distance is great. Like paper recycling, organic waste recycling can have great benefits, negligible benefits or no benefits at all, and one of the most important considerations is the distance the compostable material has to travel - the 'composting miles.' The reason is to do with use of fossil fuel, of course. In situ composting, composting in the garden or allotment, has the advantage of composting distances amounting to yards not miles.
Another advantage of in situ composting is the benefit to wildlife, unless the composter is a closed vessel, such as a compost tumbler. The composter as a valuable wildlife habitat is often overlooked, but Ken Thompson's very lively, very interesting and very informative book 'No Nettles Required: the reassuring truth about wildlife gardening' outlines the advantages to wildlife. Ken Thompson is a researcher at Sheffield University and his book gives some of the findings of the 'BUGS project.' BUGS stands for 'Biodiversity in Urban Gardens in Sheffield.' The project was supported by the major government funder of environmental research, the Natural Environment Research Council.
Of compost heaps, he writes (Page 76, 77): 'Unfortunately, the BUGS project had neither the time nor the money to look at compost heaps in detail, but other research (much of it from Scandinavia) reveals that compost heaps are hugely important wildlife habitats in their own right. This is because warm, decaying plant material is a habitat that would otherwise be absent from gardens. Reptiles in particular like these conditions, and a survey in Bristol found that gardens with compost heaps were twice as likely to have resident slow worms as those without compost heaps. Given the appetite of slow worms for slugs, this has to be another good reason for starting a compost heap...compost heaps go a long way towards replacing a whole catalogue of wildlife habitats that would otherwise be rare or absent from gardens, and are increasingly rare in the wider countryside. Another interesting feature of compost heaps is that by providing a warm, insulated habitat, they allow many species to spread further north than they would otherwise do. Many native species live further north in compost than in any other habitat...' And, in a summary box: 'Compost heaps are...a uniquely valuable wildlife habitat...No gardener with any interest in wildlife should be without one, however lacking you may be in the raw materials.'
