All About Composting

Jan 21, 2015

By Paula Sayer, Master Gardener Volunteer

Do you keep losing your pets in your leaf piles, but feel tired at the thought of all the work involved in chopping and turning a decent compost pile? Compost doesn't have to be a lot of work.

I'm briefly going to cover 3 types of composting. We'll call them rapid composting, general composting and building leaf mold. Composting can be done any time of the year but is somewhat dependent on the outside temperature with lower temperatures slowing the process. You don't need to add any worms or microorganisms- they are naturally present on plant materials.

Rapid Composting

Rapid composting takes planning in gathering the correct ratios, and work setting it up and maintaining it, however you can be rewarded with results in 2-3 weeks. Materials will need to be chopped into ½” to 1 1/2” - it's easiest to mow leaves. Soft tissues don't need to be so small, but woody tissues should be shredded or omitted.  Combine equal parts of dry materials (leaves, straw, etc) and green plant material (grass clippings, prunings, fruit and vegetable waste) and mix thoroughly so there is no matting. Water the pile until it is moist not soggy. The pile should be at least 3 foot square to ensure adequate heat retention, and in most of our area, bins with covers may be needed to retain enough moisture.

Now the hard work. Every day for at least 2 weeks you need to turn the pile, moving the outer edges into the middle, where the temperature should me around 160°F. Hotter will kill the microorganisms making the compost, but cooler will slow the whole process down considerably. Don't add any more material to the pile unless the temperature doesn't rise within 48 hours, in which case check the moisture level, or add more nitrogen (green) material – grass clippings or ammonium sulfate. The pile should have a “pleasant” odor. A stink usually indicates too much water. Soon the volume and the heat of the pile will reduce and it will turn dark brown, then it's ready to use.

The advantage of rapid composting when done right, is it will kill many weed and seeds, insects and eggs plus many organisms that can cause disease in plants. And it is fast!

General Composting

General composting is basically the same. One difference would be if you don't chop materials into small pieces they will take longer to decompose. The carbon/nitrogen ratio and the water requirements are the same, but another difference is the less frequently you turn the pile the longer it will take to compost. The temperature will not be so high so it will not kill many seeds or diseases (in fact, my pile has been known to grow some awesome potatoes).

But what if, like me, you have a lawn of Bermudagrass, you don't trust your composting abilities to kill those seeds, but you have heaps and heaps of leaves? No matter how you pile them and water them, at the end of the winter they're still going to be just a pile of leaves. If you're lazy you can use nature's process and let the leaves decay naturally into a leaf mold.

Leaf Mold Composting

You can successfully compost leaves without green material, by making leaf mold. This is a cold process – decomposition is done by fungi whereas compost relies on bacteria. Although the end result is not as high in nutrients as compost, it is an excellent soil conditioner. It can take a long time to complete.

Leaves lower in lignin decompose faster, so ash, cherry, maple, poplar and willow break down in about a year, while beech, birch, hornbeam, oak, sweet chestnut magnolia and holly will take 2 or more years. They all tend to mat together and form an impenetrable barrier to air and water, so shredding or mowing them can help speed up the process.

There are several options, depending on space.  You can start with a really large wire-mesh bin (the leaves will shrink tremendously) Shredding will help reduce the initial volume. Water them well and cover them, increasing the amount of coverage if they dry out. Water them occasionally to keep them moist, fluff them up every year and after 2-3 years you'll have sweet smelling goodness. Personally I've had more success with stuffing leaves into old soil/compost/fertilizer bags. Pack them in, soak them, stab the bag with a fork a few times and stack them out of the way for a year or two, keeping them out of the sun or the bags may disintegrate before the leaves break down.

For more information about composting, visit this page on the web: http://anrcatalog.ucdavis.edu/Items.aspx?search=compost 


By Dustin Blakey
Author - County Director / Farm Advisor
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