My Grandpa Showed Me a Trick to Stop Weeds Without Chemicals — Here’s How It Works

If you’ve ever battled stubborn weeds growing between patio stones, driveway cracks, or garden paths, you know how frustrating it can be. They seem to pop up overnight, thriving even when your plants struggle.

Growing up, I thought the only way to get rid of them was with harsh chemicals — the kind that smell terrible, cost money, and aren’t exactly great for pets, soil, or the environment.

But then my grandpa, a man who spent 60 years tending gardens without a single bottle of weed killer, showed me a trick so simple I couldn’t believe it worked.

And the best part?
All you need is cardboard.

The Secret: Starve the Weeds of Sunlight

Grandpa walked outside, looked at the weeds sprouting between his old stone walkway, and said, “Plants can’t grow without light. So if you take the light away… they quit.”

Then he grabbed a scrap piece of cardboard — nothing fancy, just the top of an old shipping box — and placed it directly over the weeds.

“Watch what happens in a few days,” he said.

The idea is simple:
Cardboard blocks sunlight and air, two things weeds need to grow.
After a few days, the weeds underneath begin to wilt. After a week or two, the roots weaken enough that you can pull them out effortlessly — sometimes they even die off on their own.

Grandpa called it “nature’s delete button.”

Why Cardboard Works So Well

✔ Biodegradable

Cardboard breaks down naturally, adding carbon back into the soil.

✔ Pet- and kid-safe

Unlike chemical sprays, it doesn’t introduce toxins to your yard.

✔ Free or cheap

Shipping boxes, cereal boxes, and packaging scraps all work.

✔ Blocks new weeds from sprouting

Once the cardboard decomposes, you can cover the area with mulch or gravel to keep weeds from returning.

✔ Perfect for walkways and garden beds

Especially useful between pavers where roots get trapped.

How to Use Grandpa’s Method

Step 1: Cut or tear cardboard to size

Use pieces large enough to cover the weed patch completely.

Step 2: Lay the cardboard flat over the weeds

Make sure no sunlight can sneak through.

Step 3: Wet the cardboard (optional but helpful)

This helps it stay in place and start softening into the ground.

Step 4: Add rocks, bricks, or soil on top

This keeps it from blowing away and speeds up the smothering process.

Step 5: Wait

Give it anywhere from 5 days to 2 weeks depending on how tough the weeds are.

Step 6: Pull the remaining roots or cover with mulch

Either way, the weeds will be dramatically weakened or completely gone.

My Before-and-After Experience

The first time I tried Grandpa’s method, I placed cardboard over a row of weeds between my patio slabs. A week later, I lifted it and was shocked — the weeds were pale, floppy, and almost lifeless. I pulled them out with two fingers.

No chemicals.
No backbreaking digging.
Just a piece of cardboard and a little patience.

Grandpa’s Final Tip

He told me,

“If you treat the soil kindly, it’ll treat you kindly back.”

Sometimes the simplest solutions — the ones invented long before major brands sold us “fast fixes” — are still the best.