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Compost tea is amazing, especially here in Queensland, where our subtropical conditions demand a little extra love for the soil. It’s a liquid fertiliser packed with microbes, bacteria, and nutrients that can revitalise plants, improve your soil health, and ward off diseases naturally. If you want to give your garden a real boost, here’s how to make compost tea and why it’s worth the effort.
What is Compost Tea?

Compost tea is exactly what it sounds like – nutrient-rich water brewed using well-aged compost. The “tea” extracts beneficial microorganisms like bacteria, fungi, and protozoa, which help break down organic matter and deliver nutrients to your plants. Unlike chemical fertilisers, compost tea builds soil health over time and doesn’t harm the environment.
Why Compost Tea is Worth It
Here’s what makes brewing your own compost tea an amazing idea:
- Boosts Microbial Life: Healthy soil is teeming with microbes. Compost tea adds billions of beneficial bacteria and fungi that improve soil structure and nutrient cycling.
- Improves Nutrient Uptake: Plants absorb nutrients more effectively when they’re surrounded by active microbes. The tea delivers minerals like nitrogen, phosphorus, and potassium in an easy-to-access form.
- Strengthens Plants Against Disease: Spraying compost tea on the leaves creates a barrier of beneficial microbes. This helps to reduce fungal and bacterial problems like powdery mildew or rust.
- Reduces the Need for Chemical Fertilisers: A regular dose of compost tea can replace or reduce synthetic fertilisers while improving your long-term soil health.
- Great for Queensland Conditions: Compost tea retains moisture well, which is handy in our hot climate when plants are stressed.
What You’ll Need to Brew Compost Tea
Here’s your simple supply list:
- Well-aged compost (homemade or purchased – avoid fresh compost as it may be too “hot”)
- A large bucket or drum (10-20L works well for most home gardens)
- Water: Rainwater or dechlorinated tap water is best
- Air pump (optional, but helps oxygenate the tea for better microbial growth)
- Mesh bag or an old pillowcase to hold the compost
- Molasses or seaweed extract (optional, as a food source for microbes)
Step-by-Step Guide to Making Compost Tea
- Start with Good Compost: Choose well-aged compost full of life. If you spot worms and fine organic matter, you’re off to a good start. Avoid manure-heavy composts unless you’re sure they’re fully broken down.
- Prepare the Water: Fill your bucket with water. If using tap water, let it sit for 24 hours to allow chlorine to evaporate. Chlorine can kill the beneficial microbes you’re trying to cultivate.
- Bag the Compost: Place about 2-3 cups of compost into your mesh bag or pillowcase and tie it up. It acts like a giant tea bag, keeping the solids contained.
- Brew the Tea: Drop the compost bag into the water. Stir gently or attach an air pump for a more aerated brew. Oxygen is key to creating a microbe-rich tea.
- Feed the Microbes: Add a tablespoon of molasses or seaweed extract to feed the microbes and encourage rapid growth. Molasses provides sugar that beneficial bacteria thrive on.
- Steep and Stir: Let the compost tea brew for 24–48 hours in a shaded area. Stir occasionally if you don’t have a pump to keep the microbes active. If the tea smells sour, it’s gone anaerobic—dump it and start over.
- Strain and Use: Once the tea is ready, strain it to remove any large particles.
Compost Tea the Simple Way
If you want to make compost tea the simple way without air pumps or bubblers, here’s an easy method anyone can do:
Simple “No-Fuss” Compost Tea
What You’ll Need:
- A bucket (10–20 litres works well)
- 2–3 cups of well-aged compost
- Water (rainwater is best, but tap water works if left to sit for 24 hours)
- A stick or something to stir with
Steps:
- Add Compost to the Bucket:
Scoop 2–3 cups of compost straight into the bucket. No need for fancy mesh bags – it’s okay for the compost to mix directly with the water. - Fill with Water:
Top the bucket up with water. If you’re using tap water, let it sit for a day beforehand to remove chlorine, which can harm beneficial microbes. - Stir Daily:
Stir the mixture vigorously once or twice a day with a stick or spade handle. This keeps the microbes active and prevents the tea from becoming stagnant. Place the bucket near a walkway you use a lot to help you remember! - Let it Steep:
Leave the bucket in a shady spot for 2–3 days. Longer than this can turn it anaerobic (smelly and less effective). - Strain and Use:
Once ready, strain the liquid through an old cloth or sieve to remove large chunks of compost. Use the strained tea immediately for the best results. If straining is not your thing, just scoop the tea straight from the top and use. - Use the Leftovers:
The leftover compost sludge at the bottom of the bucket is still valuable – toss it back into your garden or compost heap.
Bonus Tip: If you don’t have time to stir daily, don’t stress! It’ll still work – just stir well before using to mix up the goodness.
This method is low-tech, quick, and still gives your plants a nutrient-dense, microbe-packed boost.
How to Use Compost Tea
Compost tea is versatile and can be applied in a few different ways:
- Soil Drench: Water your garden with the tea to feed plants at the roots and improve soil biology. This works wonders for vegetables, flowers, and fruit trees.
- Foliar Spray: Use a spray bottle to mist the leaves. It’s excellent for pest control and disease prevention. Do this early in the morning or late in the afternoon to avoid burning leaves in the Queensland sun.
- Seed Soak: Soak seeds in compost tea before planting to give them a strong start.
Tip: Use compost tea within 24 hours of brewing for maximum benefits. After that, the microbes start to die off.
Troubleshooting Common Issues
- Sour Smell: This means the tea has gone anaerobic (low oxygen). Aerate it more next time, and avoid letting it sit too long.
- No Bubbles: If using an air pump, a lack of bubbles could mean your pump isn’t strong enough. Aim for visible oxygenation.
- Sludge in the Bucket: Don’t panic. Strain the tea well before use (or scoop liquid from the top) and return any sludge to your compost heap.
Extra Tips for Queensland
- Feed Hungry Crops: Ginger, tomatoes, and leafy greens respond beautifully to compost tea. Apply every 2 weeks during their growth phase.
- Scale Up for Larger Gardens: Use a larger drum and a stronger pump to make bigger batches of tea. It’s perfect for veggie patches or fruit orchards. At our old property, my husband brewed compost tea in 1000L pods. He connected the pod to our water system so we could use any of the garden hoses to apply the compost tea. Brilliant!
- Protect Your Brew: Always brew in the shade. Excess heat can kill off the microbes you’ve worked hard to grow.
Final Brew
Compost tea is simple to make, costs next to nothing, and gives your garden an incredible boost. It’s like a probiotic for your plants, building resilience and improving their growth naturally. Whether you’re growing veggies, herbs, or fruit trees, a regular splash of compost tea will have your garden thriving in no time.
Give it a go this weekend – your soil and plants will thank you for it.