What Are Compostable Materials?

“Hi, we recently started a backyard farm in Montana, USA, and I’ve read that composting is an excellent way to improve soil health. However, I’m not entirely sure what materials are compostable and which ones aren’t. We have kitchen scraps, leaves, grass clippings, and even some paper waste. Can I compost those? Also, any tips or things to avoid would be really helpful!” Thanks, Carol, Helena, Montana, USA.

What Are Compostable Materials?

Composting is a fantastic way to turn your household waste into nutrient-rich soil, but the key to successful composting lies in understanding exactly what materials are compostable. Not everything that comes out of your kitchen or garden should go into the compost pile, and knowing the difference can save you a lot of hassle in the long run, Carol.

So, let’s explore what qualifies as compostable materials, how you can best use them, and a few things you should definitely leave out. I’ll also share some pointers specific to your situation in Montana! But first, let’s get to the basics.

Types of Compostable Materials

Generally, compostable materials fall into two primary categories: greens and browns. These terms refer to the nitrogen and carbon content of the organic matter you’re adding to your compost pile.

Greens (Nitrogen-Rich Materials)

“Greens” may include any organic material that’s high in nitrogen. These materials help micro-organisms in the compost pile break down matter quickly, producing the heat necessary for composting.

• Kitchen Scraps: Think vegetable peels, fruit rinds, coffee grounds, and even tea bags. These work well to provide nitrogen, but make sure to avoid adding cooked or oily foods, which can attract pests.
• Grass Clippings: Freshly cut grass is loaded with nitrogen, making it an excellent green addition.
• Green Manure: For those growing a backyard farm, green plants like cover crops (e.g., clover) can be composted when mowed down.
• Manure: Non-carnivorous animal manure (like that from cows, rabbits, and chickens) is rich in nitrogen and can be composted, though it needs proper handling.

Browns (Carbon-Rich Materials)

“Browns” are materials high in carbon and are essential to balance out the high nitrogen content in greens. They help to aerate the pile and keep it from becoming too compacted, which could slow down decomposition.

• Dry Leaves: Autumn is a great time to collect fallen leaves. These are rich in carbon and help to keep your pile balanced.
• Paper Materials: Newspaper, cardboard, and other non-glossy papers can also be added. Just be sure to shred them into smaller pieces to speed up decomposition.
• Straw and Hay: Both straw and hay function well as browns but take longer to decompose than leaves.
• Sawdust: Make sure this is untreated wood dust—no chemicals. It works as a great brown additive when used in moderation.

Zeroing In: Kitchen Waste

Given your question, Carol, kitchen waste forms a significant part of what people think they can compost. While most kitchen scraps are compostable, it’s essential to be a little selective.

Here’s a rundown on what you can compost from your kitchen and what you should avoid:

The Balancing Act: Carbon-to-Nitrogen Ratio

A successful compost pile needs the right mix of greens and browns for optimal decomposition, Carol. This balance is often measured by the carbon-to-nitrogen (C:N) ratio. The ideal ratio is somewhere around 30:1, meaning that there should be 30 parts carbon to every part of nitrogen.

You can achieve this balance by mixing around 3 parts brown to 1 part green. If your compost pile smells unpleasant, it could be due to too much nitrogen (greens); add more browns like dried leaves or cardboard. On the other hand, if it’s not breaking down quickly or seems dry, consider adding more greens or watering it evenly.

Materials to Avoid

There’s a lot you can compost, but it’s just as crucial to remember what you shouldn’t compost. Understanding this will help keep pests away and avoid introducing harmful pathogens to your compost pile.

Avoid Putting These in Your Compost Bin:

• Meat & Fish Scraps: These can attract pests like raccoons and produce foul odors as they decompose.
• Dairy Products: Although biodegradable, dairy can become rancid quickly and attract unwanted visitors.
• Oils and Grease: These slow down the composting process and can clog up your composting system.
• Diseased Plants: Be very careful not to compost any plants showing signs of disease, as the pathogens could survive the composting process.
• Pet Waste: Manure from cats, dogs, and other carnivorous pets can carry pathogens, so it’s better to keep these out.

Advanced Insights: Specialty Compost Additions

Once you’ve mastered the basic greens and browns, you can start experimenting with more unique compostable materials. Carol, these might be especially fun if you want to dive deeper into optimizing your compost:

Adding Biochar

Biochar is a type of charcoal used to enrich your soil. It’s created by burning organic materials like wood or straw at high temperatures in a low-oxygen environment. You can mix biochar into your compost to increase its microbial activity. Keep in mind biochar is an enhancer, not a main compost ingredient.

Composting Alternative Paper Products

Ever wonder about composting things like toilet paper rolls, paper towels, or even cotton fabric? Yes, these can go into the compost, as long as they’re unbleached and free from synthetic additives. They add to the brown content, providing much-needed carbon. Just be sure to shred or cut them into smaller pieces.

Bone Meal and Fish Emulsion

If you’re looking to enhance the nutrient content of your compost, adding organic fertilizers like bone meal or fish emulsion can give your plants a little extra. These materials are rich in nutrients but should be added in small amounts.

Troubleshooting Common Composting Problems

It’s not uncommon to run into some issues when you’re new to composting. Here are some tips for troubleshooting common problems you might face, Carol:

1. The Pile Smells Bad

If your compost pile starts to smell rotten, it’s usually because there’s too much moisture, or you’ve added too much green material. Add more browns and turn the pile to aerate it. In Helena, Montana, the weather can be quite varied, so if it’s humid, be extra cautious not to over-water the pile.

2. The Compost Pile Isn’t Decomposing

If your compost isn’t breaking down, it could be due to a lack of moisture, air, or nitrogen. Make sure you’ve got the right ratio of browns to greens and that you’re turning the pile regularly. Water the pile if it feels dry.

3. Pests in the Compost

Pests are drawn to food scraps like meat, dairy, and oils. If you’ve followed the guidelines and these aren’t in your pile but you still have pests, try covering your compost with a layer of browns after every addition of greens, or consider investing in a compost bin with a lid.

Practical Tips Specific to Your Location

Given that you’re in Helena, Carol, the local climate in Montana can affect your composting. The changing seasons and colder temperatures require some adjustments:

• Winter Composting: Composting can slow down significantly in Montana’s cold winters. Try insulating the pile with straw or leaves, and continue turning the compost to keep it from freezing solid.
• Dry Climate Consideration: Helena can be quite dry at times, so you might need to water your pile more often, especially if you’re adding a lot of browns.

Final Thoughts…

Carol, composting is a rewarding practice that can hugely benefit your backyard farm. Remember, the key lies in balancing your greens and browns, avoiding certain materials, and troubleshooting as you go. Stick to the basics, and don’t worry too much if things aren’t perfect right away. Before you know it, you’ll be reaping the rewards of rich, homemade compost that your garden will absolutely love.

Thanks again for reaching out with your question. Happy composting!