Most people know the basics of kitchen composting: apple cores, banana peels, and coffee grounds are fair game. But if you're only tossing in the obvious stuff, you're missing out on a huge opportunity to divert even more waste from landfills. The truth is, your green bin can handle way more than you think.
Whether you're participating in San Diego's organic waste program or maintaining a home compost system, understanding what's actually compostable can dramatically reduce the amount of trash you send to landfills. Let's explore some surprising items that belong in your compost collection, not your garbage can.
1. Citrus Peels (Yes, Really!)
You've probably heard that citrus peels don't belong in compost. This myth has been circulating for years, leaving countless orange and lemon peels to rot in landfills instead of becoming nutrient-rich soil.
The truth? Citrus peels are absolutely compostable. The misconception comes from old advice about home composting, where large quantities of citrus could temporarily slow decomposition or discourage certain beneficial insects. However, San Diego's municipal composting facilities have no problem processing citrus peels. The industrial-scale composting process easily breaks down the natural oils and acids in citrus rinds.
At home, citrus peels actually add valuable nutrients and help balance your compost's pH levels. Just tear them into smaller pieces to speed up the breakdown process. That morning, grapefruit? Those lemon wedges from last night's fish dinner? Toss them in without a second thought.
2. Cooked Pasta, Rice, and Grains
Here's where it gets interesting. While many home composting guides warn against adding cooked starches (they can attract pests and get moldy), San Diego's curbside organic waste program welcomes them with open arms.
That leftover spaghetti that's been sitting in your fridge for a week? The rice you overcooked and can't save? The oatmeal your kids refused to eat? All of it can go straight into your green bin.
Municipal composting facilities maintain high temperatures that quickly break down these items without attracting unwanted visitors. The key is using a proper collection system in your kitchen. A well-ventilated paper bag allows moisture to evaporate, preventing that gross, slimy mess that develops when cooked grains sit in sealed plastic.
Pro tip: Let cooked foods cool before adding them to your kitchen collection container. Hot food creates excess moisture and accelerates decomposition, which means stronger odors in your home.
3. Cheese and Other Dairy Products
This one surprises almost everyone. Cheese, yogurt, sour cream, butter, and even that expired milk in the back of your fridge are all acceptable for municipal composting.
Home composters typically avoid dairy because it breaks down slowly, smells terrible in the process, and attracts animals. But commercial composting facilities are specifically designed to handle these challenging materials. The high-heat aerobic decomposition process neutralizes odors and breaks down fats and proteins efficiently.
That moldy block of cheddar you discovered? The yogurt that expired last month? The cream cheese you forgot about after your bagel brunch? Don't feel guilty about the waste—just compost them. You're actually making a better environmental choice than throwing them in the trash where they'll produce methane in an oxygen-free landfill.
One caveat: avoid adding large quantities of liquid dairy all at once. Pour out most of the liquid (milk, melted ice cream) and scrape the solids into your compost bag. Your kitchen will thank you for preventing unnecessary mess.
4. Meat, Fish, and Bones
If you've been composting for a while, this might seem shocking. Traditional composting wisdom says meat and fish are absolute no-nos. Yet San Diego's organic waste program specifically accepts all meat, poultry, fish, and yes, even bones.
The industrial composting process reaches temperatures hot enough (131-170°F) to safely break down animal proteins and eliminate any potential pathogens. Home compost piles rarely get this hot, which is why backyard composters avoid these items. But your green bin? It can handle everything from chicken bones to fish heads to that pork chop your toddler refused.
This is actually one of the biggest advantages of municipal composting over home systems. Think about how much food waste this represents: the bones from last night's chicken dinner, the shrimp shells from taco Tuesday, the fat you trimmed off that steak, even the Thanksgiving turkey carcass. Instead of stinking up your trash, all of this organic matter can become useful compost.
The best practice? Collect meat scraps in a ventilated paper bag and empty your kitchen pail frequently (every 2-3 days). The ventilation holes prevent moisture buildup that causes accelerated decomposition and strong odors.
5. Seafood Shells
Shrimp shells, crab legs, lobster shells, oyster shells, clam shells—if it came from the ocean and was once alive, it's compostable. These items are rich in calcium and chitin, which break down into valuable nutrients for the soil.
San Diego residents are lucky to have access to abundant fresh seafood, but this also means plenty of shells. Rather than letting them smell up your kitchen trash, add them to your organic waste collection. The municipal composting process handles them easily, and they contribute unique nutrients that benefit the finished compost.
One note about larger shells: while your green bin accepts them, they may take longer to fully break down. Lobster and crab shells benefit from being broken into smaller pieces before composting. A quick tap with a hammer or a stomp with your foot does the trick.
6. Paper Coffee Filters and Tea Bags (With a Catch)
You probably already compost coffee grounds, but what about the filter? Good news: unbleached paper coffee filters are completely compostable. They break down quickly and add beneficial brown matter to balance out all those nitrogen-rich food scraps.
Tea bags are compostable too, but here's the catch: many tea bags contain tiny amounts of plastic to help them hold their shape. Check your tea packaging—if it says "plastic-free" or "100% biodegradable," you're good to go. Otherwise, it's safer to tear open the bag, compost the tea leaves, and trash the bag itself.
The same goes for coffee pods. Traditional K-Cups are not compostable because they're made from plastic and aluminum. However, some brands now offer compostable pods made from plant-based materials. Read the packaging carefully, and when in doubt, empty the coffee grounds into your compost and dispose of the pod separately.
7. Pizza Boxes (Even with Grease and Cheese)
That pizza box sitting on your counter? It doesn't belong in recycling—it belongs in your green bin. Grease-stained cardboard contaminates recycling streams, making it unacceptable for paper recycling. But for composting? Grease and food residue are perfectly fine.
The same goes for other food-soiled paper products: greasy paper plates, napkins with food on them, paper takeout containers, and that cardboard sandwich box from lunch. If it's made from paper or cardboard and touched food, it goes in the green bin, not the recycling bin.
This is a game-changer for reducing trash. Think about how often you get takeout or delivery. Those paper bags, cardboard containers, and napkins—all compostable. Just remember: no plastic-coated paper or containers with plastic windows. When paper is coated with plastic (like many frozen food boxes), it needs to go in the trash.
8. Nut Shells (Most of Them)
Peanut shells, pistachio shells, and sunflower seed shells are all compostable. These provide valuable carbon-rich "brown" material that helps balance nitrogen-heavy food scraps.
The one exception? Walnut shells. Black walnuts contain juglone, a natural compound that can inhibit plant growth. While San Diego's composting process breaks this down eventually, it's one of the few items you might want to skip. Regular English walnut shells are fine, though they take longer to decompose due to their density.
If you're snacking on pistachios or enjoying boiled peanuts, save those shells for your compost instead of filling up your trash can. They're actually beneficial for the composting process.
9. Moldy and Spoiled Food (All of It)
Found a science experiment in the back of your fridge? That fuzzy bread, slimy lettuce, and mystery container from three weeks ago? Perfect for composting.
Many people feel squeamish about handling spoiled food, but here's a secret: mold and bacteria are exactly what drive the composting process. That white fuzz on your strawberries? Those are decomposer organisms already doing their job. In your green bin, they'll continue breaking down organic matter alongside millions of other microorganisms.
This is where having a good system matters. Using a paper liner in your kitchen pail means you never have to touch gross, moldy food. Just scrape it directly into the bag, and when you're ready, seal the whole thing up and take it to your green bin. No contact, no mess, no problem.
The environmental impact of composting spoiled food versus trashing it is significant. When food decomposes in a landfill, it does so anaerobically (without oxygen), producing methane—a greenhouse gas 84 times more potent than carbon dioxide. In a composting facility, that same food breaks down aerobically, producing minimal greenhouse gases while creating nutrient-rich compost.
10. Hair and Pet Fur
This one sounds strange, but human hair, pet fur, and even nail clippings are compostable. They're pure protein and take time to break down, but they eventually decompose completely.
After brushing your dog or cutting your own hair, collect the trimmings and add them to your compost. Hair is actually rich in nitrogen and contains trace minerals that benefit soil. Some gardeners specifically add hair to their home compost to boost nitrogen levels.
This won't make a huge dent in your waste stream, but it's a fun reminder that "organic" really means "came from something living." If it grew, it goes—even if it grew on your head.
What Still Can't Be Composted
Now that we've expanded your composting horizons, let's clarify what still doesn't belong in your organic waste:
Hard no's for both municipal and home composting:
- Plastic of any kind, even if labeled "compostable" or "biodegradable"
- Metal, glass, and ceramics
- Treated or painted wood
- Pet waste (cat litter, dog waste)
- Cooking oils in large quantities
- Synthetic materials (rubber, foam, fabric blends)
Questionable "compostable" products:
Be especially cautious about products labeled "compostable" made from bioplastics like PLA. Many of these require specific industrial conditions that exceed what even municipal facilities can provide. They often leave behind microplastics and can contaminate finished compost. When in doubt, choose paper over bioplastic alternatives.
Making It Easy: The Right Collection System
Knowing what you can compost is only half the battle. The other half is having a system that makes it actually happen.
Here's the reality: if composting is inconvenient or gross, you won't do it consistently. This is where your collection method matters tremendously. You need something that:
- Contains odors without trapping moisture
- Prevents leaks and messes
- Makes disposal easy and touch-free
- Actually breaks down in the composting process
A ventilated paper bag checks all these boxes. The paper is sturdy enough to handle wet food waste, the ventilation reduces odors by allowing moisture to evaporate, and when you're ready to empty it, the entire bag goes into your green bin—no scraping, no cleaning, no contact with gross stuff.
Compare this to keeping scraps loose in a bin (which means cleaning the bin constantly) or using plastic bags (which contaminate the composting process and defeat the purpose). The right liner turns composting from a chore into a simple habit.
The Bottom Line
San Diego's organic waste program can handle far more than most people realize. When you expand your composting to include meat, dairy, cooked foods, and food-soiled paper, you can easily cut your trash output in half or more.
The environmental impact is real. Every pound of organic waste you divert from the landfill is a pound that won't produce methane gas. Instead, it becomes nutrient-rich compost that improves soil health, helps plants grow, and completes the natural cycle of organic matter.
Start expanding your composting this week. Next time you're about to toss something in the trash, ask yourself: "Did this used to be alive?" If the answer is yes, it probably belongs in your green bin instead.
With the right knowledge and a simple collection system, composting everything becomes second nature. You'll be amazed at how little actual trash you generate once you're using your green bin to its full potential.
Ready to make composting easier? EcoToss bags are designed specifically for maximum food waste collection. Made from 100% paper with built-in ventilation, they handle everything from citrus peels to chicken bones while keeping your kitchen clean and odor-free. No plastic, no microplastics, just simple, effective organic waste collection that actually works.
