It is sometimes difficult to know what types of foods you can place in a compost pile and what is best left out. Fish and seafood waste is an organic material which can be put in compost bins or tumblers. To keep avoid smells and vermin, dig them through deep into the pile, bury them in the ground or add them to a food waste bin to recycle them.
This article will explore the top ways to compost seafood, 5 easy methods, extra tips to reduce smells and pests and common ways to recycle them at home.
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Composting Seafood – The benefits
Around 2.3 billion pounds of seafood waste is generated every single year, and unfortunately there are only a few things you can do with seafood waste. Most of it still ends up in landfill. Prawn tails, crab shells and fish bones can all be turned into compost if you know a few easy tips. This keeps them out of landfill and turns them into valuable fertilizer.
Putting Seafood in Compost Tumblers
Tumbler compost bins are a great option to break down seafood scraps. They are off the ground and seal well which means they are less likely to attract vermin.
After placing the fish scraps in your composting tumbler, make sure you add some type of carbon or brown material to the mix, such as leaves, wood chips, or maybe even both. This will help to absorb any extra moisture, smells and will balance out your compost mix.
Adding Seafood to Compost Piles
Seafood scraps can be added right in the middle of your compost pile. Adding the scraps cover them with a minimum of six inches of material on all sides so that pests can’t find it.
Adding extra brown material like hay, straw or fall leaves will help to absorb the extra moisture that can come from fish scraps.
Shells from shrimp or lobsters do decompose, but they take a long time to do so than softer fish scraps. Break them up if you can before adding them. The smaller pieces will be easier for soil bacteria and worms to break down and digest.
Seafood shells, especially shrimp shells are great because help to create air pockets and overall airflow in your pile.
How to Prepare Seafood for Composting
The best thing to do with shells from seafood is to make sure they’re in much smaller pieces before you put them in the compost. Some people pulverize their shells, which is perfect because the small pieces will easily mix in with the rest of the compost pile.
Fish waste can be buried in your yard in a hole 12 to 18 inches deep, and they will break down naturally. Soil bacteria and worms will dig their way up and digest the seafood pieces over time.
5 Alternative Ways to Compost Fish and Seafood
Here are a few ways you can recycle fish and seafood waste turning it into compost or fertilizer to add to your soil.
1. Industrial Composting
If you own a small restaurant or you’re a seafood supplier, you can actually work with a local compost hauler who will bring all of your waste to a composting facility that specializes in industrial waste.
They are made for industrial scale composting so they can accommodate very large loads of seafood waste, and they use various methods to get the job done. These include anaerobic digestion, in-vessel digestion, or on-farm windrow composting.
2. Add it to Your Green or Food Waste Bin
Most local councils will accept seafood in green waste bins. Check with your local municipality but most will happily process this with green waste. These scraps are incorporated into the industrial composting process and are often broken down in large, drum grinders.
3. The “Bokashi” Method of Composting
This is a good at-home method of composting that uses no oxygen and some type of grain inoculant. To start, you’ll place your food scraps in an airtight container that is layered with the inoculant. With the container full, you simply set it aside for roughly two weeks, where the process is completed on its own.
Once that part of the process is complete, you simply dig a hole and bury it. Inoculants can be solid, liquid, or freeze-dried and can include peat-based products. You can find them at many nurseries and gardening centers.
4. Fish Hydrolysate
If you’re trying to compost fish, you can use the scraps to make either a liquid fish fertilizer or fish hydrolysate. One word of warning about this method: it stinks to high heaven in the first few weeks, but afterward the smell dissipates over time.
The process involves grinding your fish waste well, adding three ingredients – lactobacillus, dechlorinated water, and either molasses or brown sugar – then you have to let it sit in the container until it ferments. When the process is complete, the product is diluted and can be used to inoculate your soil or simply put in a compost pile.
One of the biggest advantages of this method is that the plants love it. This is because the hydrolysate will increase the microorganism population and even encourage fungal growth in your soil.
I like to buy fish emulsion made in this way but if you are interested, here is a video on how to make it yourself at home.
5. Black Soldier Flies
Black soldier flies have huge appetites and are often seen swarming around compost piles when it’s warm outside. The flies will lay their eggs in the waste for their offspring and eat. The end result is frass, or insect poop, which is a great fertilizer for all types of gardens.
In fact, the flies will eat half their body weight or more, which means the food waste breaks down quickly. Black soldier flies are officially called Hermetia illucens, and this is a rather “clean” method of composting fish and seafood scraps.
This will happen anyway if you leave seafood scraps on top of your compost pile. If you want to avoid the flies and encourage soil bacteria and worms to break it down, dig the seafood scraps through the pile instead.
When it comes to composting, it’s good to know that even fish and seafood waste can be broken down and used in your garden. For both fish and seafood, the tumbler composters usually work best, but you can use other methods as well. Composting both fish and seafood, even shellfish, is simple but break it up into small piece first to help it to decompose faster.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.