Compost tea is a powerhouse for your plants—a liquid infusion made by steeping compost in water to extract beneficial microbes, nutrients, and organic compounds. Whether you’re growing vegetables, herbs, flowers, or fruit trees, compost tea can improve soil biology, boost plant immunity, and encourage vigorous growth. The best part? It’s affordable, customizable, and easy to make right at home.
This guide will walk you through every option: aerated and non-aerated methods, bacterial or fungal dominant brews, ingredients, tools, and how to use your tea for optimal results.
🧠 Why Use Compost Tea?
Compost tea isn’t just a “fertilizer.” It’s a living solution brimming with:
- Beneficial microbes (bacteria, fungi, protozoa, nematodes)
- Soluble nutrients like nitrogen, phosphorus, and potassium
- Plant growth hormones
- Disease-fighting compounds
Benefits:
- Enhances microbial life in the soil
- Improves nutrient uptake
- Suppresses harmful pathogens
- Increases drought resistance
- Rebuilds poor or compacted soils
- Feeds both roots and foliage
🔬 Types of Compost Tea
There are two main types:
1. Aerated Compost Tea (ACT)
Uses air pumps to oxygenate the brew, increasing microbial activity. Ideal for general soil and foliar feeding.
2. Non-Aerated Compost Tea (NCT)
No pump needed. Simpler but less microbially diverse. Can ferment, so use quickly and carefully.
Both can be tailored to create either:
- Bacterial-Dominant Tea: Good for vegetables, annuals, grasses.
- Fungal-Dominant Tea: Better for trees, shrubs, and perennial plants.
🧪 Ingredients for Compost Tea
Essential Base:
- Finished compost (preferably homemade, vermicompost, or high-quality organic compost)
For every gallon of water, use:
- 1–2 cups compost
Optional Additives:
| Ingredient | Purpose |
|---|---|
| Unsulfured molasses | Feeds microbes (esp. bacteria) |
| Kelp powder or liquid | Micronutrients + growth hormones |
| Worm castings | Extra microbial life |
| Fish hydrolysate | Nitrogen-rich + feeds fungi |
| Humic acid | Enhances nutrient uptake |
| Rock dust or glacial minerals | Adds trace minerals |
| Alfalfa meal | Plant growth stimulant |
| Neem seed meal | Pest-suppressing microbes |
| Mycorrhizal fungi | Helps root association (don’t brew—apply directly or post-brew) |
Note: Avoid chemical fertilizers, chlorinated water, or synthetics.
🪣 Equipment Needed
For ACT:
- 5-gallon food-safe bucket
- Aquarium air pump (powerful enough for 5+ gallons)
- Air stones and tubing
- Fine mesh bag or paint strainer (for compost)
- Dechlorinated water (let tap water sit 24 hrs or use a filter)
For NCT:
- Same bucket and compost
- Stick or spoon to stir occasionally
🧼 Cleaning Is Critical
All equipment must be thoroughly cleaned before and after each batch to prevent bad bacteria or mold from taking over. Sanitize with vinegar or hydrogen peroxide—avoid bleach.
🧃 How to Make Aerated Compost Tea (ACT)
Step-by-Step:
- Fill a bucket with 4 gallons of dechlorinated water.
- Place 1–2 cups of compost into mesh bag and submerge in bucket.
- Add optional ingredients:
- 1 tbsp molasses
- 1 tsp kelp powder
- 1 tbsp fish hydrolysate
- Set up the air pump and drop air stones in the bottom.
- Brew for 24–36 hours max. Longer can lead to anaerobic conditions.
- The tea should smell earthy (not rotten).
- Use immediately after brewing for best results.
Pro Tips:
- Brew in shade at 65–75°F.
- Add more air than you think—more bubbles = more oxygen.
- If it smells bad, don’t use it!
🧃 How to Make Non-Aerated Compost Tea (NCT)
Quick Guide:
- Add 1–2 cups compost to a 5-gallon bucket of dechlorinated water.
- Add a small amount of molasses (1 tsp) to feed microbes.
- Stir 2–3 times daily for 2–5 days.
- Use quickly—fermentation can lead to pathogen buildup.
Best Used:
- As a soil drench, not for foliar spraying
- When ACT equipment is unavailable
🎯 Customizing for Your Plants
| Crop Type | Tea Type | Additives |
|---|---|---|
| Leafy greens & veggies | Bacterial | Molasses, worm castings |
| Flowers & annuals | Balanced | Kelp, humic acid, compost |
| Fruit trees | Fungal | Fish hydrolysate, alfalfa, rock dust |
| Lawns & grasses | Bacterial | Molasses, worm castings |
| Perennials | Fungal | Leaf mold compost, kelp |
🌱 How to Use Compost Tea
1. Soil Drench
- Pour at the base of plants or apply with a watering can.
- Helps inoculate soil and feed roots.
2. Foliar Spray
- Strain the tea through cheesecloth or nylon stocking.
- Spray leaves in early morning or evening.
- Avoid spraying in full sun or windy conditions.
3. Seed Soak
- Soak seeds in diluted tea (1:4) for a few hours before planting.
- Encourages germination and early root health.
🕓 How Often Should You Use It?
- Soil drench: every 2–4 weeks
- Foliar spray: weekly during growth season
- For stressed plants: once a week until recovered
🧊 Storage
Do not store compost tea. It’s a living brew—microbes will die or turn anaerobic quickly. Always use within 6–8 hours of finishing.
⚠️ Troubleshooting
| Problem | Cause | Fix |
|---|---|---|
| Smells bad | Anaerobic conditions | More air, clean gear, shorter brew time |
| No foam | Not always bad, but may mean low microbial activity | Increase microbe food (molasses/fish) |
| Visible mold | Contamination | Discard and sanitize equipment |
🌍 Compost Tea vs Compost Extract
Compost Tea = Microbe-rich liquid made with or without aeration and a carbon source (like molasses). Brewed over 1–3 days.
Compost Extract = Quick soak of compost in water for an hour or two. Contains some nutrients and microbes but fewer than tea.
Use extract for quick results, but tea for biological richness and long-term soil health.
✅ Final Thoughts
Compost tea is one of the best low-cost, high-impact practices for any gardener looking to revitalize soil, boost plant resilience, and increase yields naturally. Whether you choose aerated or non-aerated, bacterial or fungal-dominant, you’re giving your garden a probiotic superdrink that builds life from the ground up.