Serious gardeners and suppliers of composting tools have posted lots of good advice on the internet about how to compost. The focus in this article is on encouraging your best backyard friends (meet the microbes) to turn the fall tree leaf harvest into a fluffy mulch that resembles tea leaves.
The Annual Cycle
September-November: collect leaves (best if they are somewhat torn up); pile them, in contact with the ground – no walls or bin is really required; “seed” it with existing refined, active compost.
May-June: turn the pile and add green material (i.e. grass clippings- harvested before lawn weeds or grass goes to seed). It might be possible to do this again later in the season, at times when there is not much seed production in the lawn. If you have compost that is produced from other sources (i.e. black plastic bins or green cones) you can add it in to this pile…just be sure that the other compost system has been hot enough to destroy seeds and plant parts from weeds and invasive species. Do NOT add compost from worm composting, since you will likely be introducing non-native worms to the ecosystem.
August: best to turn the pile again, just to be sure that it is well mixed, air and moisture are well distributed and all parts are breaking down.
Early September: Sift compost, saving the larger bits that are screened out so that they can be used to “seed” the next batch of leaves that will be soon harvested. Place it around your garden plants as the end of the growing season approaches. As this year’s plants are removed, work the compost into the soil or pile it on top of your perennials to protect them for the winter. Alternatively, store the compost. I have two wooden cubicles that I keep mine in. Some comes into the house in a pail for use with my indoor gardening activities during the winter and spring. Some is kept in the bin until the next batch of compost is produced…always there to top up some pots or enrich around a plant that needs help.
September – November: Collect more leaves and start again! Apply what you learned in the past year.
The key to success here is having the bottom of the leaf pile in contact with the earth AND “seeding” the pile with natural organisms (microbes – a generic term for a diversity of small organisms) that expand into the pile to turn the leaves into compost. To get started, borrow some rich compost from a friend, or collect a few litres of forest floor detritus. Also, place the pile in a shady area…which will make it easier to keep it at the right level of humidity all year.
My “sifting screen” features a piece of hardware cloth (ask in your hardware store for ½ inch metal screen mesh), that is nailed to a wood frame. See the photo. I made mine to sit on top of my wheelbarrow. My design has the two long sides extended to serve as legs, keeping it off the ground during the months of storage. The short side on the “bottom” of the rectangle uses a 2x6 rather than a 2x4, so that it sits inside the lip of the wheelbarrow, preventing the screen from slipping around during use.
The leaves will break down more effectively if they are shredded during collection by using a lawnmower (i.e. a mulching lawnmower with a bagging system, or just using the mower to blow the leaves into wind rows and raking them into collection bags) or use a leaf vacuum bagger. Don’t let the compost get too dry or too wet. If you have some left over fertilizer or access to manure, you can add this to the pile to both speed the composting and increase its nutrient value. If the compost is developing quickly, you can sift a bit in mid-summer and add it around plants in your garden as a very healthy mulch…preventing weeds, reducing evaporation, holding moisture, feeding your plants and generally making your garden look beautiful.
This is not a “hot” composting technique, meaning the process will not likely kill weed seeds. Other composting methods generate more heat. Also, if you have leaves that have noticeable infections, such as the recurring “Black Spot” that is common on the invasive Norway Maples, do not put them into your compost pile, since the infection will be perpetuated in coming years. Don’t be tempted to put the seeds or parts of any invasive species into any compost system or any leaf bags that you put out for municipal collections. Follow the advice of the Ontario Invasive Plant Council (www.ontarioinvasiveplants.ca ) for bagging and destroying invasive plants.
No matter what you do with your garden organic waste, NEVER just toss it in or next to a “natural” area. This despicable practice has resulted in major infestations of invasive plants and insects in the Carolinian Zone.
How well does this work?
You are likely familiar with the brown paper bags that people place at the curb for pick up. Each year I process between 50 and 75 bags of leaves into perhaps 15 wheel barrow loads of fine compost and a wealth of healthy plants. A conversion rate reminiscent of making maple syrup! Yes, that does initially take a fair bit of space. My fall leaf pile is perhaps 4 metres by 3 metre and over a metre deep. It is a third of that size by May.
If I work at it – ensuring that all leaves are well mulched when put into the pile, turning the pile more frequently, adding fertilizer, watching the moisture level closely – I can produce high quality compost in 8 months. However, I prefer to let Nature do the bulk of the work. The schedule I’ve prescribed will give you just enough exercise to claim that you made the compost. You can decide whether to give credit to your best friends (the microbes) buried in the backyard!
Owen Williams, a CCC Director