Home Composting: The Right Stuff

With the gardening season picking up speed, it’s time to think about composting. And it’s not very complicated: any organic material will decompose when exposed to a little moisture and heat, either in a compost pile, a compost bin, or just spread around among your garden’s plants (surface composting).

However organic matter decomposes more quickly when there is about the same amount of carbon-rich materials (called brown materials) and nitrogen-rich materials (called green materials although they are not necessarily green). It is therefore useful to know whether a product is “brown” or “green” when you add it to the compost so you can add about equal amounts of its complement.

Brown Materials

• fall leaves;
• dead plants;
• used potting soil (from houseplants, container gardens, etc.);
• peat moss;
• wood chips and sawdust (in modest amounts);
• twigs;
• pine needles;
• nuts and shells;
• wood ash (in limited quantities);
• buckwheat hulls;
• cardboard egg cartons;
• coffee filters;
• hay and straw;
• paper (preferably shredded);
• cotton / wool / silk scraps.

Green materials

• garden waste (tree and shrub prunings, vegetables, herbaceous plants, deadheaded flowers, etc.)
• kitchen scraps (vegetable and fruit peelings, rotten fruit, etc.);
• leaves, stems and flowers of weeds;
• roots of annual weeds and perennial weeds without creeping rootstocks;
• lawn clippings;
• wilted cut flowers;
• coffee grounds;
• tea bags and herbal teas;
• algae;
• aquarium water (from fresh water aquariums only);
• hair, nails;
• animal fur;
• manure (cow, horse, chicken, etc.);
• feathers;
• ground up eggshells;
• pasta;
• bread, rice and other cereals.

As green materials are usually far more abundant during the summer months than brown ones, many gardeners store up a good supply of bags of fall leaves, collected the previous autumn, to mix with green materials during summer and thus maintain a good balance. An alternative is to add add shredded newspaper.

Don’t Compost These

There are products that can theoretically be composted if you are doing so on a large scale (such as in commercial and municipal composting), but that it is better to avoid putting into the home compost pile/bin. There are two reasons for this. One is that small-scale composting doesn’t necessarily heat up enough to destroy all possibly harmful microbes or plant materials. The other is that some materials just decompose too slowly to be worth using. This is the case of the following products:

• animal fat;
• meat;
• pet excrements;
• bones;
• weed seeds;
• roots of weeds with creeping rootstalks (horsetail, goutweed, Japanese knotweed, quackgrass, etc.)
• logs and large branches;
• corncobs (unless ground up);
• oyster shells (unless finely ground up).

So there you go! Composting isn’t complicated, is great for the environment, and provides great nutrients for your garden. What are you waiting for to start composting in your yard?