It might sound strange, but some of the best nutrients for your garden come from the sea. That’s right—crushed-up crab shells, shrimp husks, and lobster carapaces are packed with soil-boosting power. Known as crustacean meal, this ocean-sourced fertilizer is a quiet powerhouse in the world of organic gardening.
So, what makes it so special? Let’s dive in.
What Is Crustacean Meal?
Crustacean meal is a natural fertilizer made by grinding up the shells of crabs, shrimp, lobsters, and other sea-dwelling creatures. These shells are often leftover from the seafood industry, making this a sustainable way to recycle what would otherwise be waste. When dried and ground into a fine powder, the shells turn into a nutrient-dense meal that can supercharge your soil.
Don’t worry—you don’t need to live near the coast to take advantage of this oceanic goodness. Crustacean meal is widely available at garden centers and online.
Why Is It So Beneficial?
The secret sauce in crustacean meal is chitin, a naturally occurring compound found in the exoskeletons of crustaceans. Chitin is loaded with nitrogen and, when broken down in the soil, stimulates beneficial microbial activity. It not only feeds your plants but also wakes up the ecosystem beneath your feet.
Some of the top benefits include:
- Slow-release nitrogen: Feeds plants steadily without burning roots.
- High calcium content (about 12%): Crucial for strong cell walls, especially important for fruits like tomatoes and peppers.
- Magnesium boost: Supports photosynthesis and overall plant vigor.
- Soil health support: Attracts earthworms and nurtures the microbes that build fertile soil.
Natural Pest & Disease Defense
Crustacean meal doesn’t just feed your plants—it protects them too. When tilled into the soil, chitin tricks harmful pests like nematodes and root-feeding insects into thinking the soil is hostile. This prompts the soil microbes to produce enzymes that break down these threats before they can harm your crops.
Some gardeners even report fewer issues with root rot, powdery mildew, slugs, and grubs after using crustacean meal regularly.
How to Use Crustacean Meal in Your Garden
Using crustacean meal is easy—just keep a few best practices in mind:
🪴 For transplanting:
Mix 1–2 tablespoons into each planting hole before dropping in your seedlings. It gives your plants a strong start and deters root-eating pests right away.
🌱 For new garden beds:
Apply 5–10 pounds per 100 square feet. Work it into the top few inches of soil, ideally a few weeks before planting so the nutrients have time to become active.
♻️ In the compost:
Add it to your compost pile to speed up decomposition and add extra nitrogen and minerals. Your finished compost will be more robust and nutrient-rich.
🐌 Pest barrier:
Sprinkle around the base of plants as a deterrent to slugs, snails, ants, and even rodents (though hungry raccoons might still investigate!).
Pro tip: Always bury it or cover it with mulch to avoid attracting curious animals or birds. The seafood scent can draw unwanted visitors!
Make Your Own Crustacean Meal
Feeling crafty? You can make crustacean meal at home!
- Collect shells from crab, lobster, or shrimp (from dinner or seafood restaurants).
- Clean them well, removing any meat or fat.
- Dry thoroughly—use a dehydrator, oven on low heat, or just leave them in the sun for several days.
- Grind to a powder using a high-powered blender, food processor, or mortar and pestle.
That’s it—you’ve got your own DIY fertilizer that’s full of oceanic goodness!
A Word of Caution
While crustacean meal is safe and organic, here are a few things to watch out for:
- Make sure you’re buying 100% pure crustacean meal. Some low-quality products are cut with fillers like concrete dust or sand.
- Though it’s safe to apply generously, more isn’t always better. Stick to the recommended rates to save money and keep your soil balanced.
- Don’t confuse crustacean meal with seafood waste like leachate or fish emulsions—they’re different products with different uses.
The Bottom Line
Crustacean meal might not be the most glamorous soil amendment out there, but it’s certainly one of the most effective. Packed with slow-release nitrogen, calcium, and pest-repelling properties, it’s a versatile addition to any organic garden.
So the next time you enjoy a seafood dinner, think of it as the first step in growing your best garden yet. Your plants—and your soil—will thank you.