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A few years ago, I noticed that my neighbor’s garden was always thriving. I’m talking full, leafy greens, vibrant tomatoes, massive zucchini, and lush flower pots that looked like they belonged in a magazine. His houseplants too, everything just looked alive and healthy, no matter the season. One day I asked him, “What the heck is your secret?”

He smiled, held up his coffee mug, and said, “Coffee grounds. I save them and feed all my plants. Garden plants, houseplants, you name it. Works like magic.”

At first, I brushed it off. It sounded like too much work. I barely had time to finish a cup of coffee without a kid climbing up my leg or yelling “MOM!” from the bathroom. The idea of drying out coffee grounds, storing them, and remembering to use them in my already-too-busy gardening routine sounded… ambitious.

But eventually, I decided to give it a try. And let me tell you: it’s easy. Quick. Involves the kids. And it’s absolutely worth it. Now I save both coffee grounds and eggshells, and I’ve seen a noticeable difference in the health of my plants.

If you’ve been curious about how to use these kitchen scraps to boost your garden, let me walk you through exactly how I prepare, store, and use them- plus a few real-life tips and things I’ve learned along the way.

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Why I Started Using Coffee Grounds and Eggshells in the First Place

This all really took off when I started paying more attention to the waste in our kitchen. With two boys who love scrambled eggs and two adults who drink a lot of coffee, we were tossing a ton of potential garden gold.

I also wanted to get away from buying fertilizers and constantly hauling bags of compost back from the store. It just wasn’t realistic long-term. I figured, if my neighbor’s thriving jungle of a garden could run off coffee grounds, why not mine?

I gave it a go, starting small. One morning’s worth of grounds, one eggshell. Before long, it became part of our daily rhythm- something the kids could help with. Now, it’s second nature.

The Benefits: Why These Two Simple Scraps Changed My Garden

Coffee grounds and eggshells do so much more than I originally thought. They’re packed with nutrients, easy to work with, and best of all, free.

Coffee Grounds:

• Add nitrogen to your soil, which leafy plants love

• Improve soil structure and drainage

• Attract earthworms (which help aerate and enrich your soil)

• Help repel slugs and snails

• Slightly acidic, which is perfect for blueberries and some flowers

Eggshells:

• Full of calcium, which helps prevent blossom-end rot in tomatoes, peppers, and squash

• Break down slowly and feed the soil over time

• Can help deter soft-bodied pests when crushed

• Balance soil pH and add trace minerals

How I Prepare Coffee Grounds for the Garden

Step 1: Collect after each brew

Every time we brew coffee (which is basically daily), I scoop the used grounds out of the filter and drop them into a small countertop bin. I keep this compost bin right on my kitchen counter. It’s a convenient spot to toss coffee grounds (or eggshells as you will read below) throughout the day. The charcoal filter does a great job of keeping odors at bay, and the stainless steel design fits nicely with my kitchen decor.​ An old yogurt container or even a mason jar works if you’re just getting started.

Step 2: Dry them out

This step makes all the difference. Damp coffee grounds will grow mold if stored too long. I used to think this was a dealbreaker, but drying them is quick and can be done while you go about your day.

Here’s how:

• This foldable herb mesh drying rack has been a game-changer. I simply spread the grounds on one of the layers, and they dry evenly. Plus, it folds up neatly when not in use (and you can use it for egg shells, herbs, and more!) You can also spread them on a sheet of cardboard or baking tray and leave them out to dry in the garage or on a sunny windowsill.

• If I’m short on time, I’ll pop them in the oven at 170°F for 30 – 45 minutes. Done.

Step 3: Break them up

Once dry, I crumble them between my hands or mix them with my fingers to avoid clumping. This keeps them from creating a crust on the soil when I spread them out later.

How I store them:

I keep mine in a glass jar with a lid, labeled and stored in the garage. If I’m running low on storage space, I’ll use a freezer bag until I’m ready to use them.

How I Prepare Eggshells

This has actually turned into a fun little weekend ritual with my boys. They crack the eggs, we rinse the shells, and then it becomes a mini science project.

Step 1: Rinse well

After cracking the eggs, I rinse each shell under warm water to remove the whites and yolk. This helps prevent smells or pests later on.

Step 2: Let them dry

I lay them out on a towel by the stove or let them sit out for a day or two. If I want to speed things up, I’ll toss them in the oven at 200°F for 10- 15 minutes.

Step 3: Crush them

Once dry, we crush them. The boys love helping with this- sometimes we use a rolling pin on a ziplock bag, or if you want a finer powder, I love this mortar and pestle set. It’s sturdy, and I love the granite finish. Beyond eggshells, it’s great for grinding herbs and spices for cooking.​

Storage:

I keep a big jar under the sink and add crushed shells as we go. By the time planting season rolls around, I have plenty saved up.

How I Actually Use Them in the Garden

Here’s what I do once I’ve got a nice stash.

Coffee Grounds:

• Add to compost. I layer them with browns like cardboard, shredded paper, or dried leaves. Just don’t let grounds make up more than 20% of your compost or it may get too nitrogen-heavy. When I decided to up my composting game, this outdoor composter was a solid investment. The dual chambers mean I can have one batch finishing while adding new scraps to the other. Turning it is easy, and it speeds up the composting process

• Sprinkle around plants. I scatter a tablespoon or two at the base of leafy greens, herbs, and tomato plants.

• Worm bin food. I add a small amount to our worm compost bin as an occasional treat. They love it.

• Natural slug deterrent. I make a little barrier around lettuce and hostas with grounds. It’s not 100% effective, but it helps.

Eggshells:

• Soil amendment. I mix crushed shells directly into the soil when planting tomatoes, peppers, and squash. They release calcium slowly as they break down.

• Compost booster. Shells go right into my compost bin too. They help balance the pH and add trace minerals.

• DIY calcium water. If my tomatoes look like they need a quick boost, I soak crushed shells in a jar of water for 3 – 5 days, then water the base of the plant.

• Seed starters. I’ve even used half shells as tiny biodegradable seed pots in the spring. Just fill with soil and a seed, then plant the whole thing when it’s ready.

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What I’ve Seen in My Own Garden

The results speak for themselves. My tomato plants are stronger, my lettuce grows faster, and my compost breaks down beautifully. I’ve noticed fewer signs of blossom-end rot and better flowering in plants like nasturtiums and peppers.

We even used eggshells and coffee grounds in our indoor plants this winter, and our pothos and snake plant looked healthier than ever.

Lessons I’ve Learned Along the Way

• Always dry the coffee grounds before storing

• Don’t overdo it- too many grounds can compact and block water

• Eggshells don’t break down instantly, but they work beautifully over time

• Label your jars (learned that one the hard way- crushed eggshells and brown sugar look surprisingly similar)

• Let the kids help- crushing shells and drying grounds are easy hands-on jobs. Getting the kids involved in gardening has been a joy. This gardening set for kids comes with a tote bag, spade, watering can, rake, fork, trowel, and gloves. It’s durable and just the right size for little hands.

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If you’re trying to build a healthier garden without spending a ton, using coffee grounds and eggshells is an easy, effective way to start. It’s low effort, practically free, and a great way to get your kids involved in gardening. Plus, it just feels good to waste less and grow more.

Even if you’re not gardening on a large scale, you can still use this trick with your houseplants, patio containers, or balcony herbs. It’s flexible and forgiving, and honestly, that’s what most of us need in a gardening routine.

So next time you make your morning coffee or crack an egg for breakfast, think of it as a gift to your garden. You’ll thank yourself later.

And if you have any other gardening hacks or questions, I’m always here to chat.

Happy growing!

With love,

Bri & Cat

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