Do Crushed Eggshells Really Do Anything for Your Garden?

Ahhh yes - the eggshell myth that just won’t die. You see it all over YouTube and gardening blogs: people dutifully sprinkling crushed eggshells into their compost or garden beds like it’s magical fairy dust. But let’s be real - have you ever noticed that those little white shards never actually go away?

That’s because crushed eggshells break down incredibly slowly. We’re talking years before plants can actually use any calcium from them. That’s why you keep spotting those crunchy bits still hanging around season after season.

What Eggshells Really Do

• Tiny bit of calcium… eventually – But only if you grind them into a fine powder (think flour). Big chunky shards? Forget it, they’re just hanging out.
• Slug barrier (sort of, but not really) – Gardeners love to say shells deter slugs. In reality? Research shows slugs slime right over them like it’s a Slip ’N Slide at a backyard party.
• Aesthetic filler – They give your compost or garden bed that rustic “homestead crunch,” but the benefit is more visual than nutritional.

Better Options for Calcium in the Garden

If you actually want your plants to get calcium (and faster than a decade from now), try these instead:

• Agricultural lime – Cheap, classic, and fast-release calcium.
• Gypsum – Adds calcium without messing with soil pH too much.
• Bone meal – A double win with both calcium and phosphorus, plus it breaks down much quicker.
• Crushed oyster shells – Still slow, but more bioavailable than eggshells and can improve soil texture.

Pro Gardener Hack

If you do want to use eggshells, don’t just crush them. Bake them, then grind them into a fine powder (a coffee grinder works). That way, the calcium is actually usable within a season or two, instead of just sitting around like compost confetti.

The Bottom Line

Are crushed eggshells bad for your garden? Nope. But are they the miracle soil booster people hype them up to be? Not even close. If you’re serious about adding calcium, there are way better and faster options out there.

Still, if tossing them in makes you feel like a crunchy garden witch, go for it. Just don’t expect your tomatoes to thank you anytime soon.