As my family can attest, I’m pretty rabid about recycling. Plus, I love to garden. Add those together and it’s no surprise that we have a compost pile. In fact, until recently I had a worm bin in the pantry. It was so convenient to dump my kitchen trimmings in with the wrigglers and let them convert wilted lettuce and carrot peelings into worm castings. (Pete did not like having worms in the kitchen but he was incredibly patient with my enthusiasm.)
Not only am I keeping plant waste out of the landfill, recent research from Colorado State University’s soil lab concluded that homemade compost is the best soil amendment. They tested 40 commercially bagged products on the market, and homemade compost surpassed all of them. Plus, it’s free!
How do you make compost? There are only a few “rules.”
Make it big enough.
Create a pile that’s at least three feet in each dimension. This is big enough to contain the heat of decomposition, and to stay damp while the microbes do their job. You’ll have to figure out what is available where you live; I just save up plant matter until I have enough to build a pile. You can enclose the pile or not—it’s purely a cosmetic decision.
Use about half “brown” material and half “green” material.
Browns provide carbon. They include dead, dried leaves and straw, corn stalks left over from fall decorating, the weeds you pulled last month… you get the idea.
Greens include anything fresh and, well, green. Most veggie kitchen waste goes into this category. So do grass clippings (although it’s also good to leave those on the lawn to feed your grass. Freshly pulled weeds, bolted lettuce and spinach, coffee grounds, even human hair fit into this category. Greens provide the pile with nitrogen.
Keep your pile moist and aerated.
Not soggy—it will start to smell. (You may need to cover it with a tarp if the rain gets out of hand.) Not dry—nothing will rot. Damp, like a wrung out sponge. All those decomposers need both oxygen and moisture to survive.
Do not add….
- Meat or fat—they attract mice and other problem animals.
- Eggshells and ashes. Unless your soil is very acidic (unlikely here in Colorado), leave out eggshells and especially any wood ashes (they have an extremely high pH!).
- Salt. Salt build-up is a huge problem in an arid region such as Colorado, and many amendments add even more. Homemade compost can be virtually salt-free. Food scraped from plates after a meal might have salt in it, so think before you add that to your kitchen bucket.
- Potato peelings. They often carry scab, a disease that reduces yield and quality of your potato crop. It persists indefinitely in the soil, so don’t introduce it via peelings in your compost bin.
- Weed seeds. You don’t want to spread those seeds, and they will probably survive the composting process. Watch for flowers too. Many weeds can mature seeds even after the plant is uprooted.
- Pathogens. Leave out anything that might be diseased. In particular, tomato vines are frequently infected with some sort of blight, so I don’t compost them.
- Manures. For safety, don’t use droppings from any animal that eats meat—there are too many parasites and diseases that can end up on your fruit or veggies (ewww). For herbivores (horses, chickens, rabbits, etc.), let their manure sit for a couple of months first. That allows any pathogens to die before you add them to your garden.
That’s about it. Nature will take its course; your pile will rot.
You can speed up the process by chopping the contents into smaller pieces. I have a small electric shredder, and a power lawnmower works well on fall leaves. Turning the pile to bring the outer debris to the inside also allows the microbes to get to every piece of plant material. These activities are strictly optional, however. Your compost is finished when it is uniformly dark and crumbly and smells like humus.
Earth Day is this Sunday. I like to think of this day as a time to thank God for the amazing planet He has created for us, and a chance to consider how I am doing in obeying His mandate that we are to care for it (see Genesis 2:15).
What do you do to be a good steward of God’s creation?