After the post on homemade liquid fertilizer, which if regularly applied will give your crops a good and fast boost to grow strong and healthy, it is high time that I also say a word about compost making. Compost is a more long term and slow release measure. It is the best way to keep your soil healthy and to maintain soil fertility. This is the basis for strong and healthy crops.
Compost
Compost basics
Compost is nature's (or God's) way to maintain soil fertility. Organic matter is digested by a multitude of microorganisms that dwell in good soil and recycled to release nutrients back into the soil where they are available for your crop.
Compost always has a neutral pH thereby stabilising soil pH in contrast to a number of inorganic fertilziers that acidify soil.
Compost has a negative electric charge. This is an important quality as it enables soil to mobilize the postitively charged nutrients and to exchange them with the crop. This is called Cation-Exchange-Capacity. Soils devoid of this may be rich in nutrients but will still be unable to provide them to the crop.
Compost also improves soil structure, water holding capacity and aeration of the soil. This supports crops by providing sufficient water to crops and at the same time avoiding root rot. Soil rich in compost will be crumbly and easy to till while at the same time protected from erosion.
Compost is rich in beneficial microorganisms. They play an important role in crop health and nutrient uptake.
Sufficient amounts of high quality compost together with regular homemade liquid fertilizer applications will supply your soil with adequate amounts of all necessary nutrients to grow a plentyful, strong and healthy crop.
Compost always has a neutral pH thereby stabilising soil pH in contrast to a number of inorganic fertilziers that acidify soil.
Compost has a negative electric charge. This is an important quality as it enables soil to mobilize the postitively charged nutrients and to exchange them with the crop. This is called Cation-Exchange-Capacity. Soils devoid of this may be rich in nutrients but will still be unable to provide them to the crop.
Compost also improves soil structure, water holding capacity and aeration of the soil. This supports crops by providing sufficient water to crops and at the same time avoiding root rot. Soil rich in compost will be crumbly and easy to till while at the same time protected from erosion.
Compost is rich in beneficial microorganisms. They play an important role in crop health and nutrient uptake.
Sufficient amounts of high quality compost together with regular homemade liquid fertilizer applications will supply your soil with adequate amounts of all necessary nutrients to grow a plentyful, strong and healthy crop.
Organically grown cauliflower
In order to reach greater numbers of farmers I recorded a series on soil fertility together with UTUGI Tv. One of the topics was compost making. This post is for all of you who weren't able to watch it.
Recording with UTUGI Tv
How does compost happen?
Compost is the end product of decompostion processes happening in nature. Decomposition is the process of microorganisms feeding on organic matter (including other microorganisms or their excrements), digesting it and excreting the broken down products. This is a very complex process that includes millions of different microorganisms. It works best in environments rich in these microorganisms and environments that provide favourable conditions for microorganisms.
Think of these microorganisms as your "Soil-Cattle". They need feed, drinking water, air to breath and shelter to protect them from heavy rain or burning sun. If you remember this you know almost everything there is to know about compost making. Just as your cattle produces manure in its shed, your microorganisms will produce organic fertilizer in the compost heap.
If you take good care of them they will take good care of you by providing you with just what you need to grow your crops.
Think of these microorganisms as your "Soil-Cattle". They need feed, drinking water, air to breath and shelter to protect them from heavy rain or burning sun. If you remember this you know almost everything there is to know about compost making. Just as your cattle produces manure in its shed, your microorganisms will produce organic fertilizer in the compost heap.
If you take good care of them they will take good care of you by providing you with just what you need to grow your crops.
What do microorganisms feed on?
Microorganisms feed on organic matter. Organic matter can be fresh and green like fresh leaves, weeds, hedge cuttings, but also food scraps and fresh manure. This kind of organic matter we classify as Nitrogen-rich. This is required to grow any crop.
Microorganisms can only digest Nitrogen-rich materials though, if they have acess to Carbon-rich materials at the same time.
Carbon-rich material is organic matter that is dried up, yellow or brown material like dry leaves, straw, harvest residues, maize stover, etc.
In our compost we need to provide the microorganisms with a balanced mix of both Nitrogen-rich, green materials and Carbon-rich, brown materials.
All plants contain different amounts and combinations of nutrients and micronutrients. To get a good amount and variety of all nutrients into our compost it is important to use a good variety of different organic matter sources (e.g. weeds) in our compost.
Microorganisms can only digest Nitrogen-rich materials though, if they have acess to Carbon-rich materials at the same time.
Carbon-rich material is organic matter that is dried up, yellow or brown material like dry leaves, straw, harvest residues, maize stover, etc.
In our compost we need to provide the microorganisms with a balanced mix of both Nitrogen-rich, green materials and Carbon-rich, brown materials.
All plants contain different amounts and combinations of nutrients and micronutrients. To get a good amount and variety of all nutrients into our compost it is important to use a good variety of different organic matter sources (e.g. weeds) in our compost.
What do you need to make compost?
Choose a location for your compost that is convenient in terms of moving e.g. manure from your cow shed to the compost site and also in terms of moving the finished compost to your field.
Besides that choose a location that is protected, e.g. under a tree. This is important to shelter your compost (and the microorganisms) from heavy rain and sun.
The spot you choose should also enable to you to make a number of compost heaps next to each other, either in a row or in a circle. The compost will be ready for harvest within 3 months. Therefore you need enough space to make a number of compost heaps over a period of 3 months. After that you can remove the first compost heap and make the new heap in the same space. So if you make 1 compost per week, you need 12 square meters for the heaps and a bit of space for you to move around. Making composts next to each other in a succession will allow microorganisms to move quickly from one heap to the other according to the development stage the heap is in as different microorganisms are needed at different stages.
This brings me to the next point - make your compost on soil. Do not make your compost on concrete or a polythene sheet as the microorganisms need to be able to move in and out of the heap freely. That does not mean that you have to clear the ground or even dig a whole. Microorganisms are so small that they cannot be seen with the naked eye. They can easily move past roots and grass, no need to remove them first.
Constructing a compost in a whole might even be harmful as it would obstruct air movement within the heap. We have to ensure good air movement as our microorganisms need oxygen.
During heavy rains water would collect in a whole and the bottom part of the compost would drown. Microorganisms need water, but they don't like to go swimming :-)
Besides that choose a location that is protected, e.g. under a tree. This is important to shelter your compost (and the microorganisms) from heavy rain and sun.
The spot you choose should also enable to you to make a number of compost heaps next to each other, either in a row or in a circle. The compost will be ready for harvest within 3 months. Therefore you need enough space to make a number of compost heaps over a period of 3 months. After that you can remove the first compost heap and make the new heap in the same space. So if you make 1 compost per week, you need 12 square meters for the heaps and a bit of space for you to move around. Making composts next to each other in a succession will allow microorganisms to move quickly from one heap to the other according to the development stage the heap is in as different microorganisms are needed at different stages.
This brings me to the next point - make your compost on soil. Do not make your compost on concrete or a polythene sheet as the microorganisms need to be able to move in and out of the heap freely. That does not mean that you have to clear the ground or even dig a whole. Microorganisms are so small that they cannot be seen with the naked eye. They can easily move past roots and grass, no need to remove them first.
Constructing a compost in a whole might even be harmful as it would obstruct air movement within the heap. We have to ensure good air movement as our microorganisms need oxygen.
During heavy rains water would collect in a whole and the bottom part of the compost would drown. Microorganisms need water, but they don't like to go swimming :-)
Rough branches
Start by laying out the shape of your compost heap with a layer of rough branches. I like to work with a base of around 1 square meter. The size does not really matter. A heap that is too small will dry out quickly, so avoid making it too small. But there is really no limit on the upper end. In fact in Germany we used to make huge compost heaps with the help of a tractor . I like the 1 square meter now as it can be easily and quickly done without becoming a burden. Priority should always be to keep your compost making simple. Objective is to make enough compost for your fields. You need about 10-12 cubic meters per acre per year.
The bottom layer of rough branches will assist in air circulation. Air can easily move in through the rough branches at the bottom of the heap.
The bottom layer of rough branches will assist in air circulation. Air can easily move in through the rough branches at the bottom of the heap.
You need a pole of about 1,5 m length as thick as your arm. This pole is NOT needed as a thermometer. It is only needed during construction of the compost heap. It is in the centre of the heap and the compost is build around it. After finishing the compost heap this pole is removed from the heap and will leave a whole in the heap going all the way through the heap from bottom to top. This will form the "chimney" that will encourage air movement through the heap. It will be sucked in through the rough branches at the bottom of the heap and move upwards through the chimney and exit the heap at the top.
Using a Shredder
Collect your fresh, green, Nitrogen-rich and your dry, brown, Carbon-rich materials. As they will be used as feed for your soil-cattle, the microorganisms, these materials should be chopped up just as you would chop the napier grass for your cows. Microorganisms are extremely small. The smaller the pieces they have to digest, the faster the process of decomposition will be. They will eventually even decompose the largest pieces of organic matter, but that might take years. As we want our compost to be ready and available in 3 months it is necessary to chop everything up to at least the size of a hand. This can be done with a machete (panga) or more comfortably with a shredder as seen in the picture. With a shredder like this even large amounts of e.g. keiapple hedge cuttings can be chopped finely in a short time. Our shredder is from Brazafric and cost around 35,000 KES. It needs electricity.
Making best use of fresh manure
 Fresh Dung |  Dry Dung |
Fresh cow dung is a rich source of Nitrogen. This is indicated by its strong smell. This smell is Ammonium (Nitrogen), which is getting lost from the dung by going into gasous form. It is going up into the air. After a couple of days the dung will be dried up. The colour will have changed from green to yellow-brown. It will no longer be a Nitrogen-rich organic matter source. It is now a Carbon-rich organic matter source. It will no longer smell of Ammonium, all the Nitrogen will habe been lost. If it was rained on even more Nitrogen will have been lost due to leaching. This is a very wasteful way of treating manure. A Nitrogen-rich on-farm source has been lost. To replace this Nitrogen through off-farm fertilziers is costly. Everyone who has access to fresh manure should make an effort to harvest and preserve as much of the Nitrogen in it as possible. The best way of doing this is by composting cow dung as quickly as possible. This can be done by collecting the dung for a week in a protected area and incorporating it in a compost heap on a weekly basis, or to build one layer of a compost daily by using the dung of each day and covering it with other materials and some soil. A new layer will be added daily until the heap has a sufficient size before a new heap will be started.
Building the compost heap
Start with a layer of fresh, green Nitrogen-rich materials like fresh grass, weeds, leaves, hedge cuttings, but also fresh dung and any kitchen wastes.
Follow the Nitrogen-rich layer with a layer of dry, yellow-brown, Carbon-rich materials like straw, dry leaves, harvest residues or even ripped up carton boxes. These Carbon-rich materials are basically the same as paper and should not be used as fodder. They can be used as rouphage for ruminants (cows, sheep, goats), but are not a feed source. If fed to your animals exclusively your animals will lose weight and stop producing milk.
It does not matter how thick these layers are exactly or if you mix up all materials and decide not to layer at all. Just remember that microorganisms are tiny and need both kinds of materials together, so don't make the layers too thick. About the height of a hand is a good guideline.
Layering just helps to assess if the blanace between Nitrogen-rich and Carbon-rich materials is about right. If you add too little Nitrogen-rich materials the decomposition process will not get started.
It does not matter how thick these layers are exactly or if you mix up all materials and decide not to layer at all. Just remember that microorganisms are tiny and need both kinds of materials together, so don't make the layers too thick. About the height of a hand is a good guideline.
Layering just helps to assess if the blanace between Nitrogen-rich and Carbon-rich materials is about right. If you add too little Nitrogen-rich materials the decomposition process will not get started.
Enriching the compost
To enrich your compost you can add some rock phosphate, which is ground phosphate-rich rock, some ash, which is rich in potassium, and some bone- or horn meal, which are rich in Nitrogen, phosphorus and potassium. Sprinkle about 2 hands full over each Carbon-rich layer or after every 40 cm of mixed layer. If you can't get any of these don't worry. Your compost will also work without. Another way of enriching your compost is by using chicken manure (rich in both Phosphorus and Nitrogen) and special plants for your Nitrogen-rich, fresh green layer. Especially valuable plants are stinging nettle, comfrey and Tithonia, same as for making liquid fertilizer. Egg shells are a good source of Calcium and can also be added in compost making. Microorganisms also quite like coffee grounds, tea leaves and sugar cane bargasse.
Don't use too much ash as it would dry out the microorganisms.
Other things that MUST NOT be added to a compost are inorganic (artificial) fertilizers. They are salts and salts kill microorganisms. Fats and oil also kills microorganisms and should not be added to the compost. Also ensure that no manmade materials end up in your compost. Batteries, plastic and metal rubbish can be toxic and poison your compost. You also don't want to cut yourself on pieces of glass or wire in your compost.
Lime does not need to be added to a compost. Compost naturally has a neutral pH. Lime is needed in your soil to neutralize Hydrogen cations in the soil, not in the compost. So always incorporate lime directly into the soil in your field.
Don't use too much ash as it would dry out the microorganisms.
Other things that MUST NOT be added to a compost are inorganic (artificial) fertilizers. They are salts and salts kill microorganisms. Fats and oil also kills microorganisms and should not be added to the compost. Also ensure that no manmade materials end up in your compost. Batteries, plastic and metal rubbish can be toxic and poison your compost. You also don't want to cut yourself on pieces of glass or wire in your compost.
Lime does not need to be added to a compost. Compost naturally has a neutral pH. Lime is needed in your soil to neutralize Hydrogen cations in the soil, not in the compost. So always incorporate lime directly into the soil in your field.
To prevent nutrient losses and to protect your compost cover it with a thin layer of good topsoil or old compost. This will also introduce a good number of miroorganisms into the compost heap, as they live in topsoil and compost. This way the decomposition processes can start immediately and you don't have to wait for microorganisms to move into your compost heap. This is like transporting your very own fertilizer factory workers into the premises.
The last step is to add about 20 liters of water (for a heap with about a 1 square meter base). This will provide the microorganisms with sufficient water needed for the decomposition processes. If you add too little water these processes will not start. If you add too much this will encourage fungus growth inside the heap. This is not wanted. If you use biogas slurry instead of dung the amount of water can be reduced as it is already wet in itself.
These steps: Nitrogen-rich layer of fresh, green weeds and fresh dung or chicken manure, Carbon-rich layer of dry matter and harvest residues, enrichments like ash, a thin layer of soil and water we call 1 layer in a compost. You can either build 1 such layer per day every time you clean out your cowshed for example, continously adding more layers daily, or you keep layering in one go until your compost heap reaches up to about your hip. It could be higher of course but I find it gets hard to work any higher than that. And I like to keep my compost making easy and enjoyable. If you want to develop a good habit of routinely making compost e.g. on a weekly basis, you should always try to keep it simple and easy. If it becomes complicated or hard work you are less likely to actually do it.
These steps: Nitrogen-rich layer of fresh, green weeds and fresh dung or chicken manure, Carbon-rich layer of dry matter and harvest residues, enrichments like ash, a thin layer of soil and water we call 1 layer in a compost. You can either build 1 such layer per day every time you clean out your cowshed for example, continously adding more layers daily, or you keep layering in one go until your compost heap reaches up to about your hip. It could be higher of course but I find it gets hard to work any higher than that. And I like to keep my compost making easy and enjoyable. If you want to develop a good habit of routinely making compost e.g. on a weekly basis, you should always try to keep it simple and easy. If it becomes complicated or hard work you are less likely to actually do it.
In the end your compost will look somewhat like this. Several layers on top of each other. Try to keep the sides as neat as possible. Otherwise the material that sticks out will dry out very fast and not decompose. You can also construct your compost inside a ring or frame of linked wire or a wooden box e.g. It makes the construction easier and protects your compost heap a bit more. But it is not necessary. The topmost layer is a thin layer of top soil and then don't forget to add a last can of water. If you started with a base of 1 square meter you will end with roughly a cubic meter of compost.
Row of composts in wire frames
The final touches
oThe last step in building your compost is to remove the pole from it's centre. This will form a nice chimney all the way through to the bottom of the heap. Keep the pole nearby, you will need it again for your next compost heap.
To protect your compost heap properly from drying out too fast and also fom heavy rain or sun, it should be covered with some blanket material. This can be long grass, banana leaves, even palm leaves or keiapple hedge branches, which will also keep out curious chickens.
Do not cover the compost with a polythene sheet. Remember, it needs air circulation, which would be stopped by a polythene sheet.
To protect your compost heap properly from drying out too fast and also fom heavy rain or sun, it should be covered with some blanket material. This can be long grass, banana leaves, even palm leaves or keiapple hedge branches, which will also keep out curious chickens.
Do not cover the compost with a polythene sheet. Remember, it needs air circulation, which would be stopped by a polythene sheet.
compost covered with grass
What next?
All you got to do for the next 3 months is to wait. And to make more compost heaps of course. If all goes well you do not need to touch this compost again until it is ready to be harvested. It does not need to be turned. Turning a compost speeds up the decomposition processes, which is helpful in colder European climates, where microorganism activity is slow. In our warm East African climate turning is not necessary. In fact turning the compost would lead to nutrient losses.
What you should do though is checking if decomposition processes are well under way in your compost heap. The first phase is dominated by microorganisms that will heat up your compost heap to around 60*C. By day 3 you should be able to see steam coming out of the "chimney" if you check early in the moning. If you place your hand inside the chimney you will feel the heat coming out. You could also stick your machete (panga) into the heap and leave it there for a few seconds. When you pull it out the blade will be hot. These are all good signs that tell you that everything is going well in your compost heap. Around day 10 the second phase starts and the heap cools down. Different microorganisms now take over the task.
If your compost heap does not go through this heating up and cooling down cycle you have done something wrong and need to take it apart and start over. The most common mistakes if it does not heat up are: use of too little Nitrogen-rich material or too little water. Add both and try again. If on the other hand it takes a long time to cool down you might have added too much Nitrogen (which is not a problem but a waste of Nitrogen-rich material) or too much water and fungus might have taken over your compost heap. In that case open the compost heap. A tale-tell sign for fungus activity are white streaks growing through the compost. Add some more Carbon-rich materials, try not to compact the materials too much and start over.
What you should do though is checking if decomposition processes are well under way in your compost heap. The first phase is dominated by microorganisms that will heat up your compost heap to around 60*C. By day 3 you should be able to see steam coming out of the "chimney" if you check early in the moning. If you place your hand inside the chimney you will feel the heat coming out. You could also stick your machete (panga) into the heap and leave it there for a few seconds. When you pull it out the blade will be hot. These are all good signs that tell you that everything is going well in your compost heap. Around day 10 the second phase starts and the heap cools down. Different microorganisms now take over the task.
If your compost heap does not go through this heating up and cooling down cycle you have done something wrong and need to take it apart and start over. The most common mistakes if it does not heat up are: use of too little Nitrogen-rich material or too little water. Add both and try again. If on the other hand it takes a long time to cool down you might have added too much Nitrogen (which is not a problem but a waste of Nitrogen-rich material) or too much water and fungus might have taken over your compost heap. In that case open the compost heap. A tale-tell sign for fungus activity are white streaks growing through the compost. Add some more Carbon-rich materials, try not to compact the materials too much and start over.
Steaming hot compost heap
Harvesting compost
After 3 months your compost should be ready to be harvested. The easiest way is to take it apart with a garden fork, but also a fork hoe will do the job.
Parts of the composted materials will not be decomposed completely. They were either too large or too dry or solid Carbon. They will take a little longer to decompose fully. They need to be seperated from the finished compost. That is best done by throwing the compost through a large sieve. To construct such a sieve we have build a large wooden frame and covered it with chicken wire. If you lean it against a tree or a stick at an angle you can easily throw the compost against it. The finished compost falls through the wire piling up as a neat heap of beautiful compost, and the bigger, not decomposed parts will remain in front of the sieve. These parts can be used instead of topsoil in the next compost heap and will just continue to decompose until they have also turned into beautiful compost.
Parts of the composted materials will not be decomposed completely. They were either too large or too dry or solid Carbon. They will take a little longer to decompose fully. They need to be seperated from the finished compost. That is best done by throwing the compost through a large sieve. To construct such a sieve we have build a large wooden frame and covered it with chicken wire. If you lean it against a tree or a stick at an angle you can easily throw the compost against it. The finished compost falls through the wire piling up as a neat heap of beautiful compost, and the bigger, not decomposed parts will remain in front of the sieve. These parts can be used instead of topsoil in the next compost heap and will just continue to decompose until they have also turned into beautiful compost.
The finished compost is a stable product. It does not decompse any further. It can be stored in a protected place. Now it can even be covered with a polythene sheet (as seen in the picture below) to protect it from being washed away by rain. In this state air circulation is no longer needed.
You can also use it in your field immediately. You can apply it broadcast and incorporate it into your soil during land preparation. You can also fill it into your planting rows or holes. It does not burn seeds or plants. You can also use it any time as a mulch/ topdressing between the rows in a standing crop. It is a safe product. No protection is needed during handling.
You can also use it in your field immediately. You can apply it broadcast and incorporate it into your soil during land preparation. You can also fill it into your planting rows or holes. It does not burn seeds or plants. You can also use it any time as a mulch/ topdressing between the rows in a standing crop. It is a safe product. No protection is needed during handling.
Women harvesting compost
A word about weeds...
A lot of plants that we consider these days as weeds have traditionally been used as food or medicine. We have lost a lot of this indigenous knowledge. But even if we don't know the use of a particular plant, that doesn't mean this plant is useless. If for nothing else, we can use it as an organic matter source and turn it into wonderful compost to replenish our soils. Weeds are a good source of different nutrients, especially micronutrients. They are valuable for compost making. In fact that is the best use for what we consider weeds.
Of course we don't want to spread weeds through our compost. Therefore weeds should always be weeded before they go into seed stage. If you wait until it has gone into seed a lot of the nutrients that were originally stored in its leaves will actually have moved into the seed and the value of the leaves for compost making will be minimal. Secondly, when you do your weeding at seed stage a lot of the seeds will fall to the ground and multiply. By weeding at an early stage you will subsequently reduce the need for weeding in the following years.
However, even if seeds enter the compost heap, that is not a problem. As the compost heap heats up to around 60*C for several days, this will kill most seeds. Cells of most organisms burst at temperatures over 42*C and will thus be destroyed. This is also true for a good number of crop diseases. They will not be spread through compost. It is as if the composed material has been sterilized. Some notorious diseases like bacterial wilt though do not get destroyed by heat. Tomatoes, capsicums and potatoes affected by bacterial wilt MUST NOT be composted.
Of course we don't want to spread weeds through our compost. Therefore weeds should always be weeded before they go into seed stage. If you wait until it has gone into seed a lot of the nutrients that were originally stored in its leaves will actually have moved into the seed and the value of the leaves for compost making will be minimal. Secondly, when you do your weeding at seed stage a lot of the seeds will fall to the ground and multiply. By weeding at an early stage you will subsequently reduce the need for weeding in the following years.
However, even if seeds enter the compost heap, that is not a problem. As the compost heap heats up to around 60*C for several days, this will kill most seeds. Cells of most organisms burst at temperatures over 42*C and will thus be destroyed. This is also true for a good number of crop diseases. They will not be spread through compost. It is as if the composed material has been sterilized. Some notorious diseases like bacterial wilt though do not get destroyed by heat. Tomatoes, capsicums and potatoes affected by bacterial wilt MUST NOT be composted.
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