before we go into the issue on hand (is leachate good or bad?), it's good to have a clear understanding of the basic process involve in making a compost. if one is not clear with the process, then you won't be able to identify where the problem is. and most important, you won't be able to come up with a solution to resolve that problem ...

a compost will have the following:
1. biodegradable materials rich in carbon. this are simply the brown (dry) stuff you see all around - dried leaves, wood chips, saw dust, cardboard, newspaper, etc ...
2. biodegradable materials rich in nitrogen. this are simply the green (fresh) stuff you see all around - green leaves, vegetable scrap, fruits, fruit peelings, banana stalks, etc ...
the ideal (based on studies) ratio of carbon to nitrogen material is 25-30 carbon to 1 part of nitrogen ... it's pointless to follow this exactly to the letter, as different materials will have different levels of carbon and nitrogen in it ... unless your only using one type of material for each ... all you need to remember is that in your compost, you put a lot more brown than green, for me, i simply just put 90% brown and 10% green at the start and then adjust the mixture as i go along depending on how the materials are breaking down ...
3. bacteria that will breakdown the materials above ... to help mother nature speed up the process, some use activators. in simple terms it's just making a lot of bacteria in concentration (soil + yeast + brown sugar + water and mix occasionally for 24-48 hours) and then introducing them to your compost, rather than letting nature takes it's course and start breeding the bacteria from scratch inside the compost ...
4. water that will serve as the initial medium for the bacteria to start the ball rolling of breaking down the materials ... the materials should be moist (wet but not soggy). it's very relative 🙂 he he he ... from experience you will be able to determine how much water to put in your compose. also take note that if you use green materials that have a high water content, when its broken down, more water will be in your compost ... e.g. it's pakwan (watermelon) season now, and my family eats about 1-2 pakwans a day which i also put (e.g. leftover peels) into my compost 🙂 ...

2 methods of creating compost:
1. anaerobic process - this process uses bacteria that does need oxygen to break down the materials through fermentation. i won't be discussing this in detail as i have not tried this method yet. also, to do this requires a sealed/closed container (no oxygen), which means there is no way for any leachate to be produce 🙂 he he he ... if you want to know more about this, read about how bokashi fertilizers are made ... i once read a post from a member in this forum about the product EM.1 (enhanced microorganism) to make EMAS which is then use to make bokashi through fermentation ... i'm still trying to find where i can buy this EM.1 product here in marbel or gensan. once i have tried the product, i'll share my experiences to all ...
2. aerobic process - this process uses bacteria that requires oxygen to break down the materials. this is the most common way of creating compost. this is what happens when you pile up biodegradable materials on the ground and after 6 months to 1 year it becomes compost.

just take note of this 2 items, (1) whatever method you use, you will have both the anaerobic and aerobic bacteria in your compost which can be basically divided into good and bad bacteria - that's life 🙂 he he he. its just that more of one bacteria will grow in numbers depending on the method you use - if air (oxygen) is allowed to pass through the materials (e.g mixing it) during the process, then the aerobic bacteria will multiply and the anaerobic bacteria will die or become dormant and vice-versa. (2) worms and other insects are not really needed to make compost, it's the bacteria that are important to the process. they (e.g. worms, ants, other insects, etc) help in breaking down the materials by eating it and then excreting (tumatae) what they don't need, which the bacteria in the compost, again breaks down. the downside of this, pathogens (bad bacteria or microorganism) are introduce into the compost which may create problems. you cannot totally eliminate this other creatures (that's how mother nature works) in your compost unless your doing your compost in a controlled environment (e.g. manufacturing process). the thing to do is learn to control them to minimize the bad side effects.

what happens in your compost during the aerobic process? you can't see it, but there are telltale signs for you to know what's happening:

1. first phase: mesophilic organisms goes into action. this bacterias produce enzymes (complex proteins that serves as catalyst in specific biochemical reactions) that breaks down the material in the compost. these bacteria flourish in temperatures BELOW 40 degrees celcuis (104 degrees Fahrenheit) - more or less normal tempreture. The action of the mesophilic bacteria produces heat and raises the temperature in the compost, which leads to the next phase of the process.
pardon the scientific jargon 🙂 he he he ... in laymans term, this are good bacteria that are most active in normal tempreture, they break down the compost materials using enzymes (think of it as "parang laway ng tao") to eat and survive. as it eats, it also multiply itself, and the more of them eat and multiply, the more heat is generated in the compost ...

2. second phase: thermophilic organisms are also good bacterias. as the temperature in the compost rises, mesophilic bacteria begin to die or becomes dormant, and the populations of thermophilic bacteria increases. these bacteria thrives at temperatures above 40 degrees celsius (104 F). they break down waste material quickly (they also produce enzymes) compared to mesophilic bacteria. the high temperatures created by the thermophilic process also has the benefit of killing harmful pathogens in the compost. when the temperature in the reactor goes ABOVE 70 degrees celsius (160 F), thermophilic bacteria becomes inactive, and the temperature begins to drop. when the materials has cooled sufficiently, mesophilic bacteria returns, and the reactor's product is considered to be mature compost.

another thing to note, these 2 phases will normally happen at the same time in the different areas of the compost. when you feel the side of the bin and it's warm to the touch, you know it's in the 2nd phase, those that are not warm can either be in the 1st phase or completely done. so if after a few days of touching all the areas of the bin, and no area is warm, then your compost should be completely done. the berkley process mentioned that in 18 days the compost should be done, so after the 3rd week, if you did it properly, then all the bin area should be normal (not warm) to the touch.

obviously, to be able to collect leachate you need to make your compost in a bin (not in a pile) with some holes for water (leachate) to drain (water will seek it's own level and go down the lowest portion of the bin) and for you to collect it throughout the composting process. always remember that LEACHATE IS JUST A BYPRODUCT OF YOUR END PRODUCT WHICH IS COMPOST ...
with this in mind, the correct/proper amount of water that will be in your compost will mainly come from 2 sources, (1) the water you use to moisten your compose from time to time or the activator you use to speed up the composting process, (2) water that is the byproduct from the green material when it is broken down by the bacterias.
leachate, if it's odorless and dark brown in color, is mainly humic acid and fulvic acid carried away by the water as it travels downward to the bottom of the bin. both are key humic substances that is good for the soil as they hold nutrients that is releases in the soil.

now that we have a good understanding of the composting process, let's analyze it based on what others are saying why it's bad. i have been using leachate to water my garden since i started my compost 2 weeks ago. by next sunday, should be the 3rd week and let's see what happens then ... cheers

Boo!

Mine is just a pile of biodegradable material (sawdust, woodchips, vegetable scraps, waste paper, leftover food, fallen leaves, etc) contained in an area surrounded by paving bricks. Every once in a while I mix it up to bring the old material up and bury the new uncer.

Its not covered but is under the shade of a santol tree. It gets rained on during monsoon season and in the summer the top layer dries up.

Leachate seeps into the underlying soil. One time I was mixing up the pile I discovered that the santol tree has grown root upwards into the pile. So I guess that means the leachate is not bad?

@ joey81, we have the same logic and thinking 🙂 ha ha ha ... in my case, a long time ago, my grandfather ("lolo" ; rest in peace my idol) told me then, the best place to plant something is the place where you put your "binubulok na mga dahon" ... the term composting was still never heard 🙂 he he he ... as you said, if the soil is absorbning all those things (leachate) and still be the best place to grow plants, then logic tells you, how can it be bad? 🙂 ... in my opinion, people who said this, was doing something wrong in the process, and that can be proven through some simple actual testing ... give me 1-2 weeks until my first compost is completed, and i should be able to have an idea of what's wrong in what their doing ... i have been watering my plants with leachate for the past 2 weeks, which was the byproduct of the berkley process (aeorobic) for composting ... if it's bad, then my plants should have been dead by now, but their not. their still alive and growing great 🙂 ... cheers

Boo!

why leachate got a bad reputation? 🙂 ...

if you look at things on a bigger scale, the composting process is basically the same process that happens in a garbage landfill (e.g. the famous smokey mountain in PH) - pile up (in layers) garbage material in a landfill, cover it up, and let it decompose over a period of time. in the process, leachate is produce. we all know how toxic the leachate produce in a garbage landfill. this is due to the indiscriminate disposal of garbage waste in a society. this is the main reason why goverment and environmental groups are so concerned about leachate (from any source) seeping into the ground. just mention leachate as a byproduct and it's always associated with "toxic". as such, in some developed countries now, even backyard composting is controlled by the goverment. in a couple of years, the same thing might happen in PH ...

in addition to this, as of now, there is no specific single test (series of test needs to be done) to determine if a compost and it's leachate byproduct is safe for plants, and humans for the matter. what's worst is that goverment agencies, environmental organizations, and even scientists for that matter could not agree on a standard for these test/s to determine if a compost and its byproduct is safe to use or not ...

leachate as a byproduct of composting, contains a lot of intermediate compounds ... these are basically compounds that are still complex and requires some additional process (by micro organisms) to break it down to a more basic state ... the type of intermediate compounds in your leachate and its concentration is DEPENDENT ON A LOT OF FACTORS (variables) from the FEEDSTOCK (materials you use), the RATIO (mix of the materials), the ENVIRONMENT (where you do composting) and the PROCESS of your composting ... as such, the leachate produce in one compost will most likely be different from that of another compost ... some of these intermediate compounds can contain phytotoxic chemicals, bad for the plants. you really cannot prevent this phytotoxic chemicals in your compost unless you have a controlled setup (e.g. environment, materials, mix, process) like in a manufacturing process in which you can analyze the leachate coming out of the compost ... being bad to plants can be a lot of things, (1) worst, it's really toxic to all plants, (2) it can be toxic to some plants but not to others due to it's concentration before and after it has been diluted with water ... now you see why other gardeners are saying it's good while and others are saying it's bad. it basically boils down to the variable factors that is use in making the compost and producing leachate in the process 🙂 ...

due to the complexity of identifying/testing which is a "good" or "bad" leachate from the above, a more practical approach is to totally prohibit the byproduct leachate from seeping into the ground so as not to have any adverse effect in the environment if its bad. from a regulatory standpoint, it's the most practical approach, which is why goverments and most concerned groups advocate this. it's the reason why big compost manufacturers treat leachate as a waste byproduct that needs to be treated ("sanitize") before they can release it into the environment. the problem with this approach is that it assumes that all leachate are created equal and is really bad. if it's bad, then you prevent it from harming the environment. if it's good, then no harm done as the environment remains the same - you still have other ways of enriching your soil like buying fertilizers (inorganic or organic) or compost which by the way is also good for business and the economy and everyone is happy 🙂 he he he ...

the above was based on my understanding of a number of articles, studies, and documents i have read in the internet which i have taken into account in my composting process with the purpose of using the leachate byproduct as an additional means of increasing the productivity of my garden. now that we know the reason why compost leachate sometimes turns out to be bad, we can then look at a workable solution to the problem ... cheers

Boo!

the big question now is ... is it safe to use compost leachate in your garden? 🙂 ...

for me, the answer is YES ... provided that you are able to have some control of the variables to ensure your compost is properly made. this in turn will result in a compost leachate that is safe to use in your garden. water mix with compost leachate should be sprinkled at the base (around) of the plant and not on the leaves as what other are saying. this is to ensure that the leachate gets some additional treatment in the soil by the micro-organism before it gets into the plant through it's roots ...

ways to control the quality of your leachate ... starting from the source of your material to the process you use for composting ... how to at least ensure that your leachate is safe:

1. ensure your feedstock (materials) are organic and with no possibility of being tainted by chemicals. to have some consistency in every compost batch that you make (also the leachate byproduct you produce), always use the materials that are always readily available (abundant) in your place - for my case, its saw dust, dry leaves, green banana leaves, and kitchen organic waste.

2. the ratio (ideal is 25-30 parts brown to 1 part green) is hard to follow for backyard composting, so for me i just start with 90% brown + 10% green. if you constantly use the same materials as input, over a period of time you should be able to have a good idea of the proper ratio to use for your compost.

3. always remember that the purpose of water in your compost is to help in the breakdown of the materials and not to produce leachate. so as what the experts says keep it "moist" (wet) but not soggy. for me, i just add 1-2 liters of water when i see that my compost (1/2 of plastic drum) starts to dry - dig about 6" from the top of your compost to see if it's still moist.

4. first 4 days of your composting process don't mix the materials. after that, mix (turn the compost bin 3-5 times) your compost every 2 days. it's critical to mix in order to ensure that you perform the aeorobic process and not the aneorobic process in composting.

5. when using leachate, others say to use a 10:1 ratio with water. but for me, to be on the safe side, i use a 20:1 ratio (e.g. 250ml of leachate to 5 liters of water) in case the intermediate compounds in the leachate is too much - there is no harm in using a higher dilution, it just takes more time to use up your leachate.
when you water the plants with leachate, water the soil around the plants and not the leaves of the plants.
why? if the leachate has a lot of intermediate compounds in it, then it will be safer to put it in the soil for the other micro organism to continue and break it down rather than on the leaves which will directly be absorb by the plant - possible burning of the leaves due to high acidity.
other say it's not the dilution but more of letting the leachate stand for a few days to complete the break down of the intermediate compounds. if your using a higher dilution (20:1) in your mixture, then it follows that the leachate you produce in your compost will be use over a few days. this will give additional time for the intermediate compounds to be broken down before you use it :-).

6. same in IT ... document, test, and review the results of your usage of the leachate to have your own basis to confirm that your leachate is safe for your plants. the compost/leachate that you produce in your own backyard will be different from the others because of too many variables in backyard composting ... unlike in IT wherein you can see results instantly ... it takes time and patience with mother nature ... you can only speed up mother nature to some extent but at the end of the day, it will take time to see the results 🙂 ...

if your still hesitant to use leachate for your plants ... just use it to water your garden plot soil or a pile of soil with no plants ... it will be rich in nutrients in a few days or a week and you can then use it for your plants 🙂 he he he ... at the end of the day, it's your decision whether to use your leachate byproduct in your garden ... i hope this information helps ... cheers

Boo!