Friday, February 26, 2010

About that compost...

So, um….yeah, you know the rash promise I made? That I was through talking about compost for now? Well, my intentions were honorable, but how can I ignore the plea of a reader? After reading my previous posts, the question remained, “Okay, compost is good, I get it. What the heck is it?”
Compost is a soil amendment or a medium for growi10-11-07_1705ng plants that is created by decomposition of organic debris.  Composting is a natural process; it starts when vegetation falls to the ground.  As it slowly decays it provides nutrients needed for microorganisms, plants, and animals.  If you have walked through the forest, you have seen compost on the ground-lovely humus that is dark brown or black and has a soil-like, earthy smell.

Compost that is purposefully created is ready sooner than at nature’s measured pace and usually produces temperatures high enough to destroy pathogens and weed seeds that natural decomposition does not destroy. Ready to use compost is available in bags at nurseries and home improvement stores or in bulk from compost producers where you can pick it up or have it delivered.
Compost makes terrific mulch, but not all mulch is compost!! Some mulches, such as bark or wood chips are organic materials, but they have not been composted. The larger the pieces, the longer it takes to decompose. During the years you are waiting, all the available nitrogen in the soil beneath these mulches is utilized by the microbes doing the work, leaving none available for your plants. It kind of defeats the purpose of mulch!  Other mulches, like gravel, are inorganic and will never biodegrade. These have their own specific uses, but it is not to make the soil more fertile.
Not all compost is created equal. Be sure your compost is 100% vegetative materials or, if you prefer, contains a small amount of horse, chicken or cow manure.  I was once talked into buying compost that contained “biosolids”-perfectly safe, completely sanitized, ecologically friendly, right? While spreading the mulch, I encountered band-aids and other debris that had me ready to put my house up for sale.
Don’t go there; I don’t care what they tell you.  In a Biosolids Fact Sheet presented by the EPA, I found that “Limitations of biosolids composting may include:
• Survival and presence of primary pathogens in the product.
• Dispersion of secondary pathogens such as Aspergillus fumigatus, particulate matter, other airborne allergens.
• Lack of consistency in product quality with reference to metals, stability, and maturity.”
I don’t know what the heck Aspergillus fumigatus is, but I know for certain I don’t want it.
If you are shopping for compost, you will also run into soil and blends. One thing at which compost does not excel is filling raised beds-for this you need topsoil. There are many compositions which are sold as “topsoil”; a common “3 way mix” contains soil, sand and compost. Sometimes sawdust is included, sometimes manure. In my opinion, these do not serve well as mulch.  However, if you try to use straight compost to fill your beds, you will battle the forces of decomposition for a long, long time. The compost will continue to decompose and compact over time, your bed will sink and you will end up having to dig up all your plants and redo it. If this sounds like the voice of experience, that is because it is.
You can also make your own compost. All composting requires three basic ingredients:
1.       Carbon (Brown): dead leaves, dry grass, straw
2.       Nitrogen (Green): grass clippings and other vegetative waste
3.       Water
The water is necessary to help breakdown the organic matter. Having the right amount of greens, browns, and water is important for compost development.  The preferred ratio of brown to green materials should be about 3 to 1.  If you have too much brown, you’ll still get compost, it’ll just take a little longer. If you have too much green, you’ll likely have a smelly pile of rotting vegetation. The smaller the pieces are, the faster it will break down, so chip or shred what you can. At its most basic: make a pile with the shredded greens and browns; moisten with water. It should be the dampness of a squeezed sponge. Add a little soil or finished compost to provide some microbes. Turn with a pitchfork every week or two and in one to four months you’ll have your own compost.
The EPA has a terrific website about composting with all kinds of information, including composting facilities by state and helpful publications.  If you are interested in this topic, there is more info on the web than you could possibly assimilate. From expensive tumbling manufactured composters to composting fall leaves in plastic bags; from what NOT to compost to the chemical analysis of carbon to nitrogen ratio of various materials. Whatever you want to know, it’s out there. So, Google it!


  1. I can't believe making compost is so complicated. No wonder mine never did help the plants! Thanks for the recipe.

  2. Really, composting can be as simple or complicated as we make it. We want to speed it up, heat it up, make it go! I have an area in my woodland where i pile my garden debris. I do nothing else-no watering (it gets rain); no layering(except what occurs naturally as I add to the pile, no turning. In less than a year it produces the most beautiful compost you've ever seen. So, don't be discouraged from trying, it can be as easy as you choose!