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Black walnut shells can be used for a surprising number of practical, creative, and garden-friendly purposes.
If you’ve ever cracked a few black walnuts and ended up staring at a pile of hard shells, you might be wondering what you can do with black walnut shells instead of tossing them in the trash.
Turns out, those tough, gritty shells are actually one of the most versatile natural materials you can keep around the house and garden.
In this post, we’ll walk through the best ways to use black walnut shells, from abrasive cleaning to garden mulch, so you can get real value out of every last piece.
Let’s dig in.
What Can You Do With Black Walnut Shells?
There are dozens of uses for black walnut shells, but here are the ones that deliver the most value for most people.
1. Use Them as an Abrasive for Blasting and Polishing
One of the most common industrial uses of black walnut shells is as a blasting medium.
Crushed black walnut shells are hard enough to strip paint, rust, and grime, yet soft enough that they won’t damage delicate surfaces.
That’s why they’re used to clean airplane parts, turbine blades, and even soft metals.
You can buy crushed black walnut shells at most hardware stores and use them in a sandblasting setup for gentler results than sand.
2. Turn Them Into a Natural Scrub
Finely ground black walnut shells make an excellent exfoliant.
Many natural skincare brands use black walnut shell powder in facial scrubs and body washes because the particles are just rough enough to slough off dead skin without being too harsh.
You can make your own scrub by mixing a spoonful of finely crushed shells with coconut oil and a few drops of essential oil.
Just be gentle and don’t scrub too hard, especially on sensitive skin.
3. Polish Metal and Wood
Because black walnut shells are abrasive but not scratchy on most surfaces, they work great as a polishing agent.
You can use crushed black walnut shells in a tumbler to polish brass, copper, and even wooden parts.
Jewelry makers and hobbyists often turn to black walnut shells for this exact reason.
It’s a natural alternative to chemical polishes that can be harsh on your hands and the environment.
Ways to Use Black Walnut Shells in the Garden
The garden is where black walnut shells really shine for most homeowners.
1. Make a Long-Lasting Mulch
Black walnut shells break down slowly, which makes them a durable mulch for garden beds.
Spread a layer around your plants to suppress weeds, retain moisture, and give your garden a tidy, rustic look.
One thing to keep in mind is that black walnut shells contain juglone, a natural compound that can be toxic to some plants.
That means you should avoid using black walnut shells around juglone-sensitive plants like tomatoes, peppers, and azaleas.
Stick to using them near juglone-tolerant plants like hostas, daylilies, and most shrubs.
2. Use Them as a Drainage Layer
Black walnut shells make a fantastic drainage layer at the bottom of potted plants.
Just add a one-inch layer of shells before you add your potting soil.
The shells create air pockets that help excess water drain away, which prevents root rot.
They also break down very slowly, so you won’t have to replace them for years.
3. Deter Pests and Slugs
Slugs and snails hate crawling over sharp, rough surfaces, and crushed black walnut shells are just that.
Sprinkle a ring of black walnut shells around your garden beds or potted plants to keep those slimy pests away.
It’s an all-natural, chemical-free way to protect your plants.
4. Add Them to Your Compost Pile
Black walnut shells can be composted, but they take a long time to break down.
That’s actually a good thing if you want to add structure and aeration to your compost pile.
Just don’t add too many at once, and avoid using the finished compost around juglone-sensitive plants.
Creative and Household Uses for Black Walnut Shells
Beyond the garden and workshop, there are plenty of clever household uses for black walnut shells.
1. Make a Natural Dye
Black walnut shells are rich in tannins, which makes them a fantastic natural dye.
Simmer the shells in water for an hour or two, strain, and you’ve got a rich brown dye for fabric, yarn, or even wood.
Just wear gloves while you work because the dye will stain your hands for days.
2. Use Them as Fireplace Kindling
Dry black walnut shells burn hot and slow, which makes them great for starting fires or adding to a wood stove.
They’re also a smart way to use up the leftover shells after you’ve cracked open a batch of nuts.
3. Make Craft Projects
Crushed black walnut shells can be used in craft projects like homemade ornaments, mosaics, or decorative candle holders.
Their rich brown color and rough texture make them a unique material for anyone who loves working with natural elements.
4. Use Them for Pet Bedding
Believe it or not, crushed black walnut shells are sometimes used as bedding for small animals like hamsters and rabbits.
They’re absorbent, low-dust, and naturally resistant to odor-causing bacteria.
Just make sure the shells you use are clean and free of any chemicals.
So, What Can You Do With Black Walnut Shells?
Black walnut shells can be used for a wide range of practical, creative, and garden-friendly purposes.
From abrasive blasting and natural scrubs to garden mulch and homemade dye, these tough shells have way more value than most people realize.
Just remember to keep the juglone issue in mind if you’re using them around plants.
With a little imagination, you can turn a pile of leftover shells into something genuinely useful.
Hope this post has helped you see just how many things you can do with black walnut shells.