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Managing a Compost Pile


Temperature

After the pile has been made, let it sit for a day or two.  Take a temperature reading from the center of the pile.  If you don't have a thermometer, just stick your hand in the middle of the pile.  If you've never made compost before, the amount of heat generated by what you have built, will come as a surprise to you, no matter that you've read about it.  I'm still amazed by the whole process after many a compost pile.  A temperature of 150-160 degrees F., indicates that the microbial life is flourishing.  It is important to achieve as high a temperature as possible to be sure of killing all undesirable elements (pathogens, weed seeds, insects).  If the temperature is lower, or not rising at all; the microorganisms are starving for Nitrogen.  Immediately mix in sources high in nitrogen; blood meal, LOTS of manure, or a chemical nitrogen compound.

The smell of ammonia coming from the pile is a sign of too much nitrogen; and you need to add more carbonaceous material (sawdust, dried leaves, etc.).  If the pile smells foul at any time, it has probably gone anaerobic.  You will need to turn it much more frequently to get oxygen into it (perhaps daily for awhile).  If the pile hasn't heated up by 3 4 days, and it isn't too wet, you may have to add more nitrogen or water, or both.  The experienced composter will strive to manage the pile so that few odors are produced; smells usually indicate a loss of valuable nutrients.

The population of microorganisms inhabiting the pile changes constantly as temperature varies; each group performing its own functions in the decomposition process.  With all parts of the pile eventually passing through the high heat of the pile, the weed seeds, plant pathogens, and pesticides are broken down and destroyed.  As the following chart shows, even most human pathogens and parasites are killed.  The temperature and speed of the decay are also a deterrent to the attraction of rats or other vermin after the kitchen garbage.  After the pile reaches its highest temperatures (lasting for a week or two), it starts to cool slowly.  This is not a cause for concern, as it allows some of the other organisms to get into the act; the fungi and some types of bacteria operate at the lower temperatures, in the less warm areas of the pile.  The compost pile is a sort of microbe city, teeming with one population explosion after another of various decomposer organisms.


(It is important to note that the Pathogen Temperature Kill chart shown below is only a guide to the effects of temperature on pathogens and parasites; actual kills seldom reach 100%, as it is difficult to be positive that all areas of the pile are exposed to the high heat.)

 
Turning

Turning is probably the most often heard complaint of the composter, or would-be-but-except-for composter.  Well, you don't have to turn your compost.  If you are willing to wait many times longer than you have to for a lower quality product, then just pile your materials in the bin ... and wait ... and wait.  Unturned piles work best (as best as they can), when enough dry and coarse material is included to try to keep it aerobic.  In such piles, decomposition proceeds largely through the action of various fungi (often producing a recognizable mushroom-like smell).

To ensure that aerobic decomposition takes place; that high internal temperatures are achieved to kill pathogens, weed seeds, insect larvae, etc.; and to produce the best quality product in the shortest amount of time ... you turn your compost.  It's that simple.  So if you want the best, adopt an appropriate attitude (stoic, exercising, zen, whatever works for you), and just do it !  After the pile has been sitting for a few days, turn it into the adjoining bin with a pitchfork (or spading fork; shovels just don't seem to work as well, but will do if you have no fork).

The manner in which you turn your compost is important.  An effort should be made to turn the top and outside edges into the center of the adjoining pile or bin (this leaves the center of the first pile to place on the top and edges of the second pile or bin).  This is done every time the pile is turned to make sure that all sections of the pile go through the center, where the temperature is the highest.  For best and fastest results, the compost should be turned every few days (at least twice a week for the first two weeks, when the important high temperatures are present ... afterwards, if you like, you can get by with turning once a week).

Inspection

The turning process assures that oxygen is available to keep the pile aerobic; that all areas of the pile pass through the hot center; and provides the opportunity to examine the pile for moisture content and odor.  If extreme odors are present, correct as explained above.  The material should be wet enough to squeeze together and look damp, but dry enough to crumble apart easily when released from pressure.  A well made compost pile will yield steam as it is turned (indicating the high internal temperatures).  Turning will cool the pile down for a few hours, but temperatures will quickly rise again in a good compost mix.

When should you make compost?  ALL THE TIME.  Your household is always producing waste.  When outside temperatures are cooler, the compost will take longer to make, but is still worth making.  Protect the pile from winter rains.  Earthworms are particularly active in the cooler months.


Temperature/Time to Kill Common Pathogens/Parasites
Organism Temp.  (F) / Time
Salmonella typhosa 140 / 30 min.
Trichinella spiralis (larvae) 131 /  1 min.
Brucella abortus or B.suis 142 /  3 min.
Streptococcus pyogenes 129 / 10 min.
Shigella sp. 131 / 60 min.
Micrococcus pyogenes 122 / 10 min.
Mycobacterium tuberculosis 151 / 20 min.
Corynebacterium diptheriae 131 / 45 min.
Entamoeba histolytica (cysts) 113 /  3 min.
Taenia saginata 131 /  3 min.
Necator americanus 113 / 50 min.
Ascaris lumbricoides (eggs) 122 / 60 min.

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