For years, I’d crack an egg, scoop out the good stuff, and chuck the shell right into the bin without a second thought. It felt like the natural thing to do. But a few months ago, something clicked—I started rinsing those shells and stashing them in a jar on the counter instead. Turns out, they’re little powerhouses I’d been wasting all along.
Eggshells are basically 95% calcium carbonate, with traces of magnesium, potassium, zinc, and iron tossed in. That’s the same stuff that keeps our bones and teeth solid. They’ve got three layers: a crunchy outer shell of calcium crystals and two inner membranes packed with keratin that act like a natural bacteria shield. Who knew?
I’ve rounded up 13 ways I’ve been putting them to work—some for the garden, some for me. Read on, try a couple, and pass it along to your mates. They’ll thank you.
1. Turning eggshells into something I can actually eat
First, give the shells a good rinse to get rid of any egg goo. Then boil them for 10 minutes—kills off any nasties like salmonella. Spread them on a tea towel to air-dry, or pop them in the oven at about 200°F (93°C) for 10-15 minutes until they’re bone-dry and snappy.
Once cool, blitz them in a blender, coffee grinder, or just bash them with a mortar and pestle until you’ve got a fine powder. The finer, the better—your body absorbs the calcium easier that way.
2. Sneaking the powder into my meals
I stir a tiny pinch—half a teaspoon at most—into whatever I’m eating. Smoothies, porridge, yogurt, soup… it vanishes, no weird taste. I’ve even mixed it into banana bread batter or sprinkled it over a salad. Just don’t go mad; too much calcium can tax your kidneys.
3. Feeding the garden soil
If eating them isn’t your thing, the garden will happily take them. Crushed shells break down fast and release calcium plus other minerals into the earth. Collect enough over a week or two, and you’ve got a proper soil boost.
4. Calming angry skin
Grind some shells, mix with a splash of apple cider vinegar, and let it sit a few days. The liquid that forms is an old-school trick for soothing itchy or irritated patches. Works a treat on minor rashes.
5. Better drainage for plants
Before planting, dig a little hole, drop in a layer of crushed shells, then add soil and your plant. It improves airflow and stops the roots sitting in water. They’ll rot away eventually, so top up now and then.
6. Eco-friendly scrubber
Pulverised shells are brilliant for scrubbing stubborn bits off pots, vases, or the coffee flask. Gentle on your hands, tough on grime—and zero plastic waste.
7. Saving tomatoes, peppers, and aubergines
These guys can get blossom-end rot from lack of calcium. Bury a handful of crushed shells near the roots when you plant them out. The calcium seeps in over time and keeps the fruit firm.
8. Snail and slug barrier
Scatter jagged shell pieces around your seedlings or lettuce. The little blighters hate crawling over the sharp edges—no chemicals needed.
9. Deer deterrent (if you’re out in the sticks)
City folks can skip this, but if deer raid your veg patch, crush shells and sprinkle them about. Apparently they can’t stand the smell. Haven’t had a nibbled cabbage since.
10. Biodegradable seed starters
Rinse a shell, poke a drainage hole in the bottom, fill with compost, and pop in a seed. Set them back in the egg carton on the windowsill. When the seedling’s ready, plant the whole thing—shell and all—straight into the ground.
11. Treat for the birds
Crush shells coarsely and scatter them in the garden. Wild birds adore the calcium, especially in spring when they’re nesting. Plus, they’ll hoover up pests while they’re at it.
12. Tweaking soil pH for prettier flowers
Hydrangeas go pink in alkaline soil, blue in acidic. If yours are too blue and you fancy pink, work crushed shells into the bed. Raises the pH gently over the season.
13. Compost gold
Toss crushed shells into the compost bin. They add minerals and help balance the mix. Just crush them first so they break down quicker.
Honestly, it’s dead simple—and I’m kicking myself for binning them all those years. Less rubbish, happier plants, and a free calcium hit. Win-win. Give it a whirl, and tag a friend who loves a good hack.