Advanced Compost Tea Calculator

Plan compost tea batches, balance ingredients, size aeration, estimate brewing time, calculate dilution, coverage, application loads, costs, and safer garden use accurately with confidence.

1. Brew Setup

Uses the selected batch volume unit.
%
%
%
%

2. Compost and Ingredients

Rates apply per litre of starting water. Change any preset value to match your recipe.

g/L
%
kg/m³
kg
kg
mL/L
g/L
mL/L
g/L
mL/L
g/L
g/L
g/L
mL/L

3. Brewing Time and Aeration

Uses the selected temperature unit.
hours
L/min/L
L/min
m
%
m

4. Water Quality

hours
mg/L
mS/cm
mg/L

5. Dilution and Application

L/m²
L
L

6. Batch Cost

Ingredient prices use the entered amount unit: compost per kilogram, liquids per millilitre, and dry amendments per gram.

W
hours

Formula Used

Compost required = Starting water × Compost rate Required airflow = Starting water × Airflow rate per litre Effective pump flow = Rated flow × Efficiency × Altitude factor × Hose factor Diluted solution = Concentrated tea × (Tea parts + Water parts) ÷ Tea parts Area coverage = Diluted solution ÷ Application rate Electricity use = Pump watts ÷ 1000 × Brewing hours Total batch cost = Ingredients + Water + Electricity + Labour + Equipment allocation

Vessel volume uses length × width × height for rectangular tanks. Cylindrical volume uses π × radius² × height. All internal volume calculations use litres.

How to Use This Calculator

  1. Select the brewing method and desired finished volume.
  2. Enter vessel dimensions or its known total capacity.
  3. Choose a preset, then edit every ingredient rate.
  4. Enter pump, diffuser, temperature, and water-quality details.
  5. Set dilution, coverage, plant, and sprayer assumptions.
  6. Add optional prices to estimate complete batch costs.
  7. Calculate, inspect warnings, then copy or export results.

Example Data

InputExamplePurpose
Finished tea volume20 LSets the target batch size.
Compost rate25 g/LEstimates compost mass.
Airflow requirement0.05 L/min/LSizes an aeration system.
Dilution ratio1 tea : 4 waterCalculates final solution volume.
Application rate0.5 L/m²Estimates garden coverage.
Sprayer size10 LCalculates required loads.

Brewing and Hygiene Notes

Use mature compost from a known source. Clean vessels, tubing, diffusers, and tools thoroughly. Avoid contaminated feedstocks or untreated manure.

Discard tea that smells putrid or strongly anaerobic. Do not assume foam proves microbial quality. Laboratory testing is required for reliable biological claims.

Avoid spraying edible portions near harvest without suitable guidance. Follow local crop safety and water regulations. Keep every batch record clear and complete.

Frequently Asked Questions

1. What does this calculator measure?

It estimates quantities, vessel capacity, airflow, time, dilution, coverage, loads, and costs. It does not test microbial populations or pathogens.

2. Can I use US gallons?

Yes. Select US gallons from the volume menu. The calculator converts values internally to litres.

3. What is a compost rate?

It is the compost mass added per litre of starting water. Use your chosen recipe or professional recommendation.

4. Does a larger pump always improve tea?

No. Air distribution, diffuser resistance, temperature, ingredients, and cleanliness also matter. Excessive agitation may create practical problems.

5. Why is delivered airflow lower?

The estimate applies pump efficiency, altitude, hose length, and diffuser capacity. Actual performance requires direct measurement.

6. How does the dilution ratio work?

A ratio of one tea part to four water parts creates five total parts. The calculator scales that ratio automatically.

7. Can I calculate applications per plant?

Yes. Select plant count as the application basis. Enter plants and diluted solution per plant.

8. What does the vessel warning mean?

The liquid may exceed capacity after headspace, foam, displacement, or loss allowances. Use a larger vessel or smaller batch.

9. Does standing remove chloramine?

It may not. Verify the disinfectant and treatment method with the water supplier. Use appropriate testing when necessary.

10. Can I save my recipe?

Yes. The local save button stores current form values in your browser. It does not send them elsewhere.

11. Is the cost estimate exact?

No. It depends on your prices, energy use, labour, wastage, and equipment allocation. Update every cost field carefully.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.