A practical guide to getting the most from your living soil amendment
Note on Freshness
Worm castings aren’t just fertilizer—they’re alive. Full of beneficial microbes that promote plant growth and soil health, these castings should ideally be used within a few days of arrival to ensure the microbial life remains active and potent.
- Soil Amendment: Feeding the Earth
To give your garden or houseplants a microbial boost, simply mix worm castings into your soil or top-dress around the base of your plants. After application, water thoroughly using rainwater or dechlorinated water. Tap water often contains chlorine, which can harm delicate microbial communities.
🧑🌾 Pro tip: If you only have tap water, let it sit in an open container for 24 hours to allow chlorine to evaporate.
- Soil or Potting Mix: The 10-20% Rule
Add 10–20% worm castings by volume when preparing a new soil mix. Whether it’s for indoor pots, balcony containers, or raised garden beds, this range delivers excellent results without overdoing it. Up to 50% won’t hurt your plants, but studies show the benefits tend to plateau after that 20 %. More than 50% can, in some cases, have a detrimental effect.
Works great in:
- Seed-starting mixes
- Compost blends
- DIY garden soil recipes
Transplanting: A Healthy Head Start
Worm castings can help reduce transplant shock and encourage stronger root development when moving plants to a new location or pot.
Here’s how:
- Dig a hole slightly larger than the plant’s current container.
- Add a generous handful of worm castings into the bottom.
- Place the plant and fill in the space with a blend of soil and more castings.
This creates a nutrient-rich pocket that supports early root establishment.
- Worm Casting Tea: Liquid Gold for Plants
Brewing a compost tea from worm castings is a fantastic way to extend their benefits, delivering nutrients and microbial life straight to the roots—or even the leaves.
- How to Make:
- Fill a 20 litre bucket with rainwater or dechlorinated water.
- Add 0.5 liters of worm castings
- Aerate with a blower or aquarium pump for 24–48 hours.
This process multiplies the microbes into a rich, living liquid fertiliser.
- How to Apply:
- Soil Soak: Apply directly to soil or dilute up to 1:20 with rainwater.
- Foliage Spray: Strain the tea well using a fine mesh (like a paint strainer), then dilute between 1:5 and 1:20 and apply with a misting spray.
Important: Worm tea is time-sensitive. It must be used immediately after brewing—once it loses oxygen, it becomes anaerobic and can harm plants instead of helping.