The three things you should never put into the compost bin are meat or fish scraps, pet waste from dogs or cats, and treated wood. Each of these creates health risks, attracts pests, or leaves toxins in your finished compost. Keep them out and your bin will run clean and safe.
My neighbor learned about meat the hard way last fall. She tossed fish scraps from a Friday dinner into her open compost bin. By morning, raccoons had ripped the lid off and scattered compost across her entire yard. They tore the bin apart looking for more food. She had to buy a new bin and start her batch from scratch. That one meal's worth of fish waste cost her three months of compost progress.
Meat and fish rot in a very different way than plant matter. They putrefy instead of composting, which means bacteria break them down without oxygen. This creates conditions where harmful organisms like botulism can grow. The smell also travels far and draws in rats, raccoons, and flies from the whole area. Even in a sealed tumbler, meat produces foul-smelling gases that make turning the drum miserable.
Pet waste from dogs and cats belongs nowhere near your compost. Their feces hold some of the most dangerous compost materials you can find. Dog waste can contain roundworm eggs that survive moderate compost temps. Cat feces often carry Toxoplasma, which is a serious risk for pregnant women and young children. Your home compost won't get hot enough for long enough to kill these organisms off.
Treated wood is the third item to ban from your bin. Pressure-treated lumber has copper and arsenic inside it. Older boards may have chromated copper arsenate inside the grain. These chemicals don't break down during composting. They pass right through into your finished product. Spreading that compost on your veggie garden puts heavy metals into the soil where your food grows. Those toxins build up over the years and don't go away on their own.
Beyond these three, a few other compost bin forbidden items are worth knowing. Coal ash changes your soil pH in ways most plants can't handle. Glossy magazine paper contains heavy metal inks. Diseased plant material can spread fungal spores to next season's crops. Cooking oils coat organic matter and block the airflow that good microbes need to do their job.
So what do you do with these items instead? Check if your city offers curbside organic waste pickup. Many towns accept meat and fish scraps in their green bins since their commercial facilities run hot enough to handle them. For pet waste, look into a pet waste digester that you bury in your yard. It breaks down feces in a sealed container away from your garden soil. Take treated wood to your local hazardous waste drop-off site.
Your compost bin works best with a clean diet of fruit and veggie scraps, coffee grounds, eggshells, yard waste, and shredded paper. These items break down fast and produce safe, rich compost you can use on any plant in your garden. Skip the risky stuff and you'll never have to worry about a ruined batch or a health scare. Stick to the safe list and your bin will reward you with dark, crumbly gold every season.
I keep a short list taped to my kitchen scrap bucket so everyone in the house knows the rules. It took five minutes to write and has saved me from at least a dozen bad additions over the past year. Your compost deserves clean inputs. Give it the right food and it will give you the best soil amendment you can make at home.
Read the full article: Compost Tumbler Guide for Beginners
