Composting is a fantastic way to recycle organic material and enrich your garden soil, but not everything in your yard or garden belongs in the compost pile. Some items, even those that seem natural or organic, can do more harm than good. This guide will help you identify common plants and materials found in Cleveland, Ohio, that you should avoid adding to your compost pile, and explain why they can be problematic.
Invasive Weeds
- What to Avoid: Plants like Japanese Knotweed, Garlic Mustard, and Canada Thistle.
- Why Not to Compost: These invasive species are tough and persistent. Even after being pulled, their roots and seeds can survive and spread in your compost. If your compost pile doesn’t reach high enough temperatures to kill these resilient parts, you could end up spreading these invasive weeds throughout your garden when you use the compost.
Diseased or Pest-Infested Plants
- What to Avoid: Tomato plants with blight, leaves from Powdery Mildew-infected plants, or any plant showing signs of fungal infection or insect infestation.
- Why Not to Compost: Diseases like blight and pests such as aphids or scale can survive the composting process if the pile doesn’t get hot enough. When you use this compost in your garden, you risk reintroducing these problems to your healthy plants.
Black Walnut Leaves and Branches
- What to Avoid: Leaves, branches, and especially the nuts of the Black Walnut tree (Juglans nigra).
- Why Not to Compost: Black Walnut trees produce juglone, a natural toxin that can inhibit the growth of many plants. This compound is especially harmful to plants like tomatoes, peppers, and other members of the nightshade family. Composting Black Walnut material can contaminate your compost with juglone, potentially harming your garden.
Grass Clippings Treated with Chemicals
- What to Avoid: Grass clippings from lawns that have been treated with herbicides, pesticides, or synthetic fertilizers.
- Why Not to Compost: Chemicals used on lawns can persist in grass clippings and survive the composting process. When these clippings are added to your compost pile, the resulting compost can contain residues that are harmful to your garden plants, reducing their growth and potentially contaminating your soil.
Poisonous Plants
- What to Avoid: Plants like Poison Ivy (Toxicodendron radicans), Poison Oak, and Poison Sumac.
- Why Not to Compost: These plants contain urushiol, a substance that can cause severe skin irritation. Composting these plants can spread the urushiol throughout the pile, posing a risk to anyone handling the compost. Additionally, the urushiol may remain active in the compost, potentially causing problems when you use it in your garden.
Meat, Bones, and Dairy Products
- What to Avoid: Scraps of meat, bones, cheese, and other dairy products.
- Why Not to Compost: While these items are organic, they break down slowly and can attract unwanted pests like raccoons, rats, and flies. They can also create foul odors as they decompose, making your compost pile unpleasant to be around.
Pine Needles and Oak Leaves
- What to Avoid: Large amounts of pine needles or oak leaves.
- Why Not to Compost: Pine needles and oak leaves are acidic and slow to decompose. If added in large quantities, they can lower the pH of your compost, making it too acidic for most garden plants. If you do choose to compost these, be sure to mix them well with other materials to balance the pH.
Large Branches and Wood Chips
- What to Avoid: Thick branches, large wood chips, or treated wood.
- Why Not to Compost: Large woody materials decompose very slowly and can take years to break down fully. Treated wood, which often contains chemicals, should never be composted, as these chemicals can leach into your compost and harm your plants.
Fats and Oils
- What to Avoid: Cooking oils, butter, and other fats.
- Why Not to Compost: Like meat and dairy, fats and oils decompose slowly and can attract pests. They can also create a greasy layer in your compost pile, preventing air and moisture from circulating properly, which is essential for composting.
Certain Yard Debris After Heavy Rain or Flooding
- What to Avoid: Yard debris collected after heavy rain or flooding, especially if the area was contaminated with sewage or pollutants.
- Why Not to Compost: Floodwaters can carry harmful bacteria, chemicals, and other contaminants. If you compost debris that has been in contact with polluted water, these contaminants can be introduced into your garden, potentially harming plants and even posing health risks to humans.
Composting is a great way to recycle organic material and enrich your garden soil, but it’s essential to know what not to include in your compost pile. By avoiding the items listed above, you can ensure that your compost is healthy, effective, and free from harmful contaminants. Remember, a successful compost pile starts with the right ingredients, so be mindful of what you add to it. Your garden will thank you for it!
