I’ve been working with plants and landscapes for over 25 years—and in that time, I’ve tried just about every fertilizer, soil amendment, and secret gardening “hack” under the sun. But you know what still surprises me?
Most people still don’t know about worm castings.
That’s right—worm castings. The unassuming, earthy byproduct of our wriggly little friends underground.
The first time I used it, I didn’t expect much. It was years ago, when I was still experimenting with ways to improve soil health for my landscape clients around Vancouver. I added a small handful of worm castings into a planting bed that had been struggling for seasons—dry soil, compacted clay, and vegetables that just wouldn’t take off.
Fast forward a month? The difference was undeniable. Plants were stronger, greener, and visibly happier. The soil was easier to work with, and even the earthworms themselves came back in droves.
That’s when it clicked.
Worm castings aren’t just a fertilizer—they’re living soil magic.
And today, I’m going to share with you everything I know about how to use worm castings to give your houseplants and garden the boost they deserve.
So, What Are Worm Castings Exactly?
Let’s get the “gross” part out of the way first: worm castings are worm poop. But before you wrinkle your nose, hear me out.
Worm castings are the end product of decomposed organic matter, processed through the digestive system of earthworms. What comes out the other end is black gold—a rich, humus-like substance loaded with nutrients, beneficial microbes, and enzymes.
Here’s what’s inside a typical handful of worm castings:
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Nitrogen (N) – for leafy growth
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Phosphorus (P) – for roots, blooms, and fruits
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Potassium (K) – for overall health and disease resistance
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Micronutrients like calcium, magnesium, iron, sulfur
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Beneficial bacteria and fungi that improve soil life and plant immunity
All in a perfectly balanced, slow-release form that your plants can absorb when they need it most.
Why Worm Castings Work (Even Better Than Most Fertilizers)
Unlike synthetic fertilizers that blast your plants with nutrients all at once, worm castings work with nature.
Here’s what makes them so powerful:
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🐛 Burn-Proof – You can’t overuse them. Seriously. No risk of “fertilizer burn.”
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🌱 Supports Soil Life – Encourages microbes, improves soil structure and texture.
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💧 Increases Water Retention – Especially helpful for pots and containers.
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✨ Improves Root Development – Leading to stronger, more resilient plants.
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🐝 Safe for kids, pets, and pollinators – No chemicals, no worries.
Whether you’re growing food, houseplants, or flowers, worm castings feed your garden from the ground up—literally.
How to Use Worm Castings for Maximum Plant Happiness
Let’s get into the juicy part: how to actually use worm castings.
You don’t need to be an expert. In fact, most of our customers at DH Garden Centre are surprised at how easy it is.
1. Top Dress Your Houseplants
Already have potted plants at home? This method is your new best friend.
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Lightly loosen the top 1–2 inches of soil in the pot.
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Add a layer (about ½ inch thick) of worm castings on top.
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Water thoroughly so nutrients seep down into the root zone.
📌 Tip: Repeat every 4–6 weeks for consistent nutrition. Works great for ferns, monsteras, pothos, and even orchids.
2. Mix Into Potting Soil or Garden Beds
If you’re repotting or starting a new garden bed, worm castings make an incredible soil amendment.
Use this general rule:
➡️ 1 part worm castings to 4–5 parts potting soil
or
➡️ 10–20% worm castings in your total soil mix
It helps new plants establish faster, reduces transplant shock, and keeps your soil biologically active.
Perfect for:
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Seed starting
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Vegetable beds
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Flower planters
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Hanging baskets
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Indoor plant refreshes
3. Make a Worm Casting “Tea”
Yes, you can steep worm castings like a good herbal tea! This makes a powerful liquid fertilizer and root drench.
Here’s how:
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Mix 1 cup of worm castings into 3 cups of water.
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Let it sit (covered) for 24 hours.
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Stir occasionally to oxygenate the mix.
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Use it immediately—either as a soil soak or foliar spray.
This “tea” is especially helpful for:
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Boosting stressed or wilting plants
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Feeding seedlings and transplants
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Keeping pests at bay with stronger plant immunity
A Real-Life Example from the Garden Centre
A few weeks ago, a customer named Marlene came into DH Garden Centre. She had a small indoor jungle of tropical plants—but her monstera hadn’t grown a new leaf in months.
She’d tried all sorts of fertilizers. Nothing worked. I asked her: “Have you tried worm castings?”
She raised an eyebrow. “Worm what?”
I handed her a small bag and showed her how to top dress her pots at home. She came back in two weeks later—with the biggest smile on her face. “Darrell, it worked! Not just new leaves—massive new leaves!”
That’s the kind of joy that never gets old for me.
Why Quality Matters: Not All Worm Castings Are the Same
One word of caution: like any natural product, quality matters.
Cheap worm castings often come from large-scale operations where worms are fed low-quality compost or waste, and the product sits in bags too long—losing its microbial benefits.
At DH Garden Centre, we source worm castings that are:
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Fresh and biologically active
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Made from clean, organic feedstock
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Free from contaminants, weed seeds, or harmful bacteria
When you open a bag from us, it should smell like healthy forest soil—rich, earthy, and alive.
Let’s Wrap It Up: Why You Should Try Worm Castings Today
If you’ve ever felt stuck with your plants—slow growth, weak roots, tired soil—worm castings might just be the gentle, natural solution you’ve been looking for.
They’re:
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Simple to use
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Safe for everyone
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Effective in both the short and long term
Whether you’re a beginner with a windowsill herb garden or a seasoned green thumb tending raised beds, worm castings give your plants a living, breathing foundation to grow from.
So if you haven’t tried them yet, what are you waiting for?
Come by DH Garden Centre in Kitsilano, and let’s chat. I’m always happy to walk you through how to use worm castings in your unique space—whether it’s a high-rise balcony or a backyard jungle.
Let’s grow something amazing together. 🌱
📍 DH Garden Centre LTD
3742 West 10th Avenue, Vancouver, BC V6R 2G4
📞 604-929-7335
🌐 dhgardencentre.com
📸 Instagram: @dh.garden.centre
📘 Facebook: dh.garden.centre160
📺 YouTube: The Plant Doctor
