Shrimp shells can be composted in regular backyard compost piles or bins. They are rich in Nitrogen, and should be considered a green material. Along with breaking down quickly, the materials that make up shrimp shells are also antifungal and help plants’ metabolisms in other ways. Credit:
However, we shouldn’t just use shrimp shells and tails. A compost pile can also break down lobster, crab, mussel, prawn, clam, and even oyster shells. Even if you don’t have a compost pile, bin, or tumbler,.
Although it may be surprising, Shrimp Shells and Tails, as well as all crustacean shells are fully biodegradable. They will decompose readily in an active compost pile, and are an excellent ingredient in any compost recipe. I’ve been using shrimp shells in my compost for years, and will share all that I’ve learned.
This is a quick and easy way to add them to an active compost pile: if you’re in a hurry, just throw them in the middle of the pile. Put them in the middle of the hot pile without washing or rinsing them. Their C:N ratio is very low, which means they will break down very quickly, which they do.
Even so, I thought some of you might be interested in the details of shrimp shells and how quickly they break down. So, I’m going to divide this article into smaller pieces because there is a lot of interesting information about how shrimp and crustacean shells break down.
Shrimp shells are a great addition to any compost pile. As an avid gardener and composter, I often get asked if shrimp shells can be composted. The short answer is yes, you absolutely can compost shrimp shells!
In this detailed guide, I’ll cover everything you need to know about composting shrimp shells, including:
- The benefits of adding shrimp shells to compost
- How to prepare shrimp shells for composting
- What conditions are best for breaking down shrimp shells
- Potential problems and how to avoid them
- Using finished shrimp shell compost in your garden
Let’s dive in!
Why Add Shrimp Shells to Your Compost?
Composting shrimp shells offers several advantages:
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Nutrient boost. Shrimp shells contain nitrogen, phosphorus, potassium and chitin – all excellent nutrients for your compost and garden soil. The shells break down slowly, providing a steady nutrient source.
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Soil structure improvement. The chitin in shells boosts microbial activity. This helps improve soil structure aeration and water retention.
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Reduced waste Composting shells keeps this nutrient-rich material out of landfills It’s an eco-friendly way to utilize food scraps.
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Pest control. As shrimp shells decompose, the chitin releases a compound called chitosan which repels fungal diseases, insects and other garden pests.
Clearly, shrimp shells offer major upsides as a compost ingredient. But there are a few things to keep in mind for successful composting…
Preparing Shrimp Shells for Composting
Before adding shells to your compost, take these steps:
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Rinse shells thoroughly to remove any residual meat or seasonings.
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Crush the shells into smaller pieces – this gives microbes more surface area to work on for faster decomposition. I use a rolling pin to crush mine.
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Consider dehydrating rinsed shells in the oven at 200°F until brittle and crunchy. This removes moisture, further speeding decomposition.
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Mix crushed shells with nitrogen-rich green materials like grass clippings before adding to your pile. This provides a balanced carbon-to-nitrogen ratio.
Taking time to properly prepare the shells prevents potential issues down the line.
Composting Conditions for Shrimp Shells
To break down efficiently, shrimp shells need:
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Oxygenation – Turning the compost periodically provides aeration for microbes.
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Moisture – Shells should be moist but not soaked. Aim for 40-60% moisture content.
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Smaller pieces – Crushed shells give microbes more surface area to work on.
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Balanced C:N ratio – Mix shells with nitrogen-rich greens like grass clippings.
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Heat – Maintain a temperature between 130-150°F, ideal for decomposition.
Meeting these conditions helps shells break down quickly without unpleasant odors.
Avoiding Potential Problems
Composting shrimp shells the right way avoids most problems, but here are some potential issues and solutions:
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Odor – Add more carbon-rich browns like leaves or sawdust to balance the nitrogen in shells.
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Slow decomposition – Turn the pile often and crush shells into tiny pieces before adding.
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Rodents or pests – Bury shells under 10+ inches of compost to discourage pests from digging.
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Reduced heat – Mix in fresh grass clippings or food waste to provide nitrogen and increase heat.
With proper preparation and care, shrimp shells can compost without issue. Keep your compost well-aerated and balanced, and problems should be minimal.
Using Shrimp Shell Compost in Your Garden
Once shells have fully broken down, your shrimp shell compost offers outstanding benefits when added to garden beds and pots:
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Mix 1-2 inches of compost into soil before planting. The nutrients and organic matter enrich soil health.
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Use compost as a side dressing around veggies and flowers during the growing season. The steady nutrient release feeds plants.
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Add compost to potting soil for indoor plants and container gardens to stimulate root growth and vigor.
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Work compost into seed starting mix to provide nutrition for sprouting seeds.
I also like sprinkling compost lightly on top of planted rows as a nutritious mulch. The possibilities are endless!
The chitin and nutrients in shrimp shell compost boost soil health, plant vigor and crop yields. It’s an invaluable, free soil amendment.
Composting Shrimp Shells is Easy and Rewarding
As you can see, composting shrimp shells is totally doable with the right techniques. While they take time to break down, the long-term soil benefits make it incredibly worthwhile.
What are shrimp shells made of
We all know shrimp, and their pesky little shells. Shrimp meat is delicious, fried, steamed, sautéed… you name it – it all tastes good. But most of the time, when we think of shells, we don’t think of how they were once part of a living thing. Well, the shell of a shrimp is made up of a few ingredients. Let’s take a deeper look into the breakdown:
Shrimp, lobster, and crustacean shells are 20–40% protein, 20–50% calcium carbonate and 15–40% chitin. If we talk about a shrimp, a lobster, a claim, or an oyster, their shells are all made of chitin, calcium carbonate, and organic protein.
Things that are part of living things can break down, and shrimp or crustacean shells are no different. Even though we think of clam and shrimp shells as hard, they can and will break down if they are composted properly.
Calcium carbonate. What is calcium carbonate made of?
The other main component of shrimp shells is Calcium carbonate, which is made of Calcium, carbon, and oxygen. The chemical formula is CaCO₃. Calcium carbonate is neither green nor brown carbon material, as it has no Nitrogen and little carbon. It is “along for the ride” in regards to composting in that it will decompose. Composted calcium carbonate adds significant amounts of calcium, but doesn’t directly feed bacteria or microbes in compost.
That being said, calcium carbonate will be very helpful for giving your garden a source of calcium. Simply top-dress you compost onto your vegetable garden to allow the calcium to naturally infiltrate your soil.
In addition to being high in Nitrogen, Chitin also has antifungal properties. Research has found that compost made from chitin reduces fungus and damp-off disease of cucumbers and other plants. So, it has anti-fungal properties. [4][5].
How to Compost Shrimp Shells
Can shrimp shells be composted?
This means that shrimp shells can be turned to compost whether they are raw or cooked. The shells will ordinarily decompose when they are allowed to be broken down by microorganisms into organic compost. Composting shrimp shells is important as the compounds got from this process are highly beneficial to the soil.
Can you put shrimp in compost?
A. Yes, you can add raw or cooked shrimp shells to your compost safely. Shrimp shells add calcium to your compost that helps plants grow strong stems. Q. Can you use shrimp as fertilizer? A. Yes, it provides a high amount of nutrients, less Nitrogen but a strong amount of Potassium and Phosphorus.
How do you compost shrimp shells?
Dig a hole several inches deep in the center of your compost pile and place your shrimp shells in. This is the hottest spot in the compost, and where microorganisms are actively working to break down compost materials. Cover with other compost ingredients. Turn your compost regularly and keep it moist to speed up the composting process.
Where should shrimp shells be placed in a compost pile?
When placing shrimp shells within the compost pile, position them in the middle of the pile rather than at the top. This strategic placement discourages pests and rodents from being attracted to the scent, which can sometimes occur with seafood scraps. Compost piles can be a bit like Goldilocks’ porridge—moisture levels need to be just right.