composting

National Composting Conference

Composting

By Jim Hole

In September 2000, Edmonton hosted the 10th annual National Composting Conference. The focal point of the conference was the Jekyll and Hyde nature of compost. So, how do we turn liabilities like dead plant matter, lumber mill waste, and manure into a manageable resource?

Climbing the C:N Tower

Delegates at the conference noted that any material to be broken down must be organic; in other words, it must contain the element carbon. Fortunately, all terrestrial life is made with carbon building blocks, so this is never a limiting factor. What can limit your compostable materials, though, is nitrogen, the same nutrient found in many fertilizers. The carbon:nitrogen, or C:N, ratio was frequently discussed at the conference. Unless the C:N ratio is within the correct range, the breakdown of organic matter comes to a virtual standstill. Ideally, the waste that you are breaking down should have a C:N ratio of 30:1.

Sawdust—a waste product many have tried to compost with frustrating results—has a C:N ratio of 400:1. Sawdust's very low nitrogen count explains why it takes so painfully long to decompose. Grass clippings, on the other hand, have tons of nitrogen, and if added to a pile of sawdust they can help to strike the right balance between carbon and nitrogen.

Moisture Balance

Finding the correct moisture balance is the second big issue in composting. In one presentation, researchers from the Agriculture and Agri-Food Canada Research Centre in Lethbridge explained the difficulty they faced with composting feed lot manure. Initially, the moisture level in manure is excessive, but after a few short weeks of hot, dry winds, the composting manure becomes too dry for proper decomposition. Whether the compost is too wet or too dry, the breakdown process slows down to a crawl. In back yards, the scale is smaller but the problem can often be the same. Ideally, compost should feel like a moist sponge that's just been wrung out. If your compost is too dry, simply water it. If too wet, turn it with a pitchfork to expose as much of the material as possible to the air.

Air

Finally, remember that compost should never be allowed to get too heavy or dense; this, too, will hinder decomposition. Regular aeration of the compost pile is critical, and easily achieved by turning the pile with a pitchfork once a week.

Where Food Begins

Compost Edmonton st albert Hole's

I spent the end of last week speaking at Canada Blooms in Toronto.

 The show is the largest of its kind in Canada and spans a full 10 days that are filled with everything to do with gardening. If you haven’t been to Canada Blooms, it is well worth making the trip to see the latest trends and get ‘revved’ for the upcoming gardening season.

One highlight for me was the opportunity to sit down with Susan Antler, the executive director of the Composting Council of Canada and chat about where the world of composting was headed. For those who aren’t aware, Susan’s organization is comprised of compost producers who are committed to encouraging the use of compost and setting quality standards for the industry.

Susan explained that the composting council is encouraging compost producers to get their compost certified under the Compost Quality Alliance (CQA) label to ensure that gardeners receive the highest quality compost possible. Currently, the federal government sets standards for things like maximum concentrations of heavy metals and human pathogens, but does not regulate for the horticultural quality of compost.

The CQA label on a bag of compost goes above and beyond government regulations and assures gardeners that not only is the compost they are purchasing safe for humans, but is also an excellent growing media for our garden plants.  

I think it is great to see initiatives like this being developed from respected organizations like the Composting Council of Canada and I hope to see more composting companies displaying the CQA label on their bags.

For more information visit Compost.org

~Jim Hole


 


A Lasagna Garden for the Lazy Gardener

Last weekend I made a Lasagna Bed in my garden. No, this is not something to sleep in or eat, but you can certainly grow food in it!

A Lasagna Bed is actually the way for lazy gardeners to make a new garden bed. The best thing about it is that you don't even have to dig up the lawn!

lasagna_garden_bed.jpg

The basic idea of a lasagna bed is to put down layers of carbon-rich materials (e.g. dried leaves, straw, cardboard, newspaper), alternated with layers of nitrogen-rich materials ( e.g. grass clippings, green material from your perennial beds and your vegetable garden, uncooked vegetable peels, coffee grinds, manure).

Combined with moisture, this carbon-nitrogen mix will feed the micro-organisms and fungi that decompose material and turn it into a nutrient-rich, growing medium.

The other bonus is that it allows you to make good use of the leaves that are all over your lawn right now and you'll also be able to use up all the green clippings you have from cutting down your perennials and mowing your lawn at the end of the year.

Here is the "recipe" I used for my lasagna bed this year:

  1. Wherever you'd like to start your garden bed, start with a thin layer of material high in nitrogen, to activate the decomposers (e.g. the fungi and micro-organisms). I used steer manure as my starter.  Then add water.
  2. Add a layer of overlapping cardboard or newspaper, to act as a carbon layer and as a weed/grass barrier, until the composting process is well on its way. Add water again!
  3. Add another thin layer of nitrogen rich material. I used clippings from my perennial beds and the green shells of the beans that I had grown this summer. Water!
  4. Add leaves. Water!
  5. More nitrogen, again. Here, I added the contents of my pots and planters. This is actually a mix of carbon (potting soil) and nitrogen (plants). Water!
  6. I still had more leaves to get rid of, so I did another layer. Plus more water!
  7. Finally, I finished things off with a layer of half-composted material from the compost pile I made last year.
  8. You can start the bed right on the lawn, but you should end up with a pile that is at least 1.5 to 2 feet high. As the material decomposes only a few inches will be left.

Now let the snow, winter, and the decomposers do their work.

In the spring, you can dig small trenches into your lasagna bed. By adding just a little bit of light potting soil for your transplants or seeds, you'll be able to plant your fruits, vegetables, and flowers right into these trenches and into your bed.

In such a rich growing medium, they'll grow amazingly!

 

Maria is a landscape designer trained and educated in the Netherlands. She owned a landscape design business for 10 years before moving to Edmonton in 2005 and joining the Hole's team. Book a landscaping design consultation with Maria Beers this fall and we will give you a FREE $25 gift certificate for our Glasshouse Bistro.