Questions & Answers
Compost tea is an aqueous solution full of biotic (beneficial microorganisms) and abiotic (including secondary metabolites, signal substances) components extracted and propagated from compost. The production of compost tea is done by aerobic (with oxygenation) processes.
The EdaTeam Microbial Tea is compost tea specifically adapted to areas of application.
Bacteria, protozoa, nematodes and fungi can be introduced into the soil through the compost tea. The organisms introduced by the compost tea are the basic length of the food chain and are thus indispensable for a fertile soil.
Compost tea is a sustainable alternative to conventional pesticides due to its disease suppressive (suppressive) effect through foliar and soil application.
No. Although nutrients are contained in compost tea, they are negligible in the nutrient balance. An essential component in compost tea are the beneficial microorganisms that stimulate metabolic processes and make nutrients contained in the soil available to plants (mineralize). If there is a nutrient deficit in the soil, fertilizer must be applied. Compost tea, on the other hand, does have a foliar fertilizing effect.
No. High disease pressure must be treated acutely and curatively. After the use of chemical pesticides, the application of compost tea is useful.
Compost tea works preventively by strengthening the plants and their natural defenses. Thus, the cause of the disease is treated to prevent its symptoms.
The EdaBiom microbial substrate should be stored at a stable ambient temperature without fluctuations.
The optimal temperature range is between 15 – 20°C.
The EdaBiom microbial substrate must be protected from drying out (55 – 65% relative humidity). Rooms with high humidity such as a storage cellar are suitable for this. If drying out does occur, the EdaBiom microbial substrate should be moistened. If the EdaBiom microbial substrate is stored for longer than 3 months, it is recommended to loosen the substrate in the bags. This avoids anaerobic zones.
Before storing the EdaLife brewing system, basic cleaning is carried out. The lid of the EdaLife brewing system should be closed after cleaning is complete and prevents contamination.
The term “Effective Microorganisms” (EM) was trademarked by Teruo Higa in 1970. EM is a mixture of approximately 80 different microorganism species that are cultured in the laboratory. Compost tea contains approximately 500,000 different beneficial microorganism species from natural substrate. Due to the high diversity, the microorganisms in compost tea can quickly adapt to locations or climate changes.
Liquid fertilizers can be added to the finished compost tea. However, negative interactions between fertilizer salts and microorganisms may occur. A recommendation can therefore only be given with reservation.
Temperature plays an essential role in the brewing process of compost tea. The optimal range is between 17-22°C. At cooler temperatures, the microorganisms multiply more slowly. At temperatures below 17°C, the brewing process should be adjusted to 36-48 hours. Temperatures of 30°C and above should be avoided as much as possible.
Microbial processes are responsible for soil fertility and the growth, vitality and disease and pest resistance of the plant. By applying compost tea, an enormous amount of microorganisms is supplied to the soil or leaf surface and brings many benefits:
No. The brewing system should always be operated at full capacity so that oxygenation works well. If only half the amount of compost tea is needed, half the amount of microbial substrate and microbial food can be used. This compost tea is to be considered as a 1:1 dilution at the end of the brewing process.
Normally, compost tea is brewed for 24-48 hours. If the compost tea cannot be applied during this time, the air pump should not be turned off but the brewing time should be extended. If the brewing system has a heater, it should be turned off. The maximum brewing time should not exceed four days, otherwise microbial diversity decreases.
Yes. Drinking water quality water without chlorine, rainwater or osmosis water is suitable for the production of EDAPRO Compost Tea. For foliar application, care must be taken that it is soft water with a water hardness below 7°fH.
Negative effects of an overdose have not been observed so far. Since the nutrients are bound in the bacteria, there is no danger of administering too much compost tea.
EDAPRO Compost Tea contains only the microorganisms that were initially present in the microbial substrate (EdaBiom). Due to this fact, the plant-strengthening effect of EDAPRO Compost Tea can only be guaranteed with the microbial substrate EdaBiom from EDAPRO.
The beneficial microorganisms in compost tea require oxygen. During the brewing process, the organisms are greatly multiplied. As soon as aeration is stopped, the oxygen contained in the solution is quickly used up. If the oxygen content drops below a certain range (<5 mg/L), anaerobic organisms establish themselves, which can harm the plant. Due to the high oxygen demand, compost tea must be applied immediately after the brewing process and is stable for up to a maximum of 4 hours.
Sap analyses are excellent for quickly deriving fertilizer recommendations or for adjusting fertigation computers in greenhouses throughout the season. However, the values are not absolute figures—they reach their limits in fertilization trials, especially those involving biostimulants.
The problem: If a biostimulant or a trace element application causes the plant to produce more biomass, the nutrient concentrations in the sap decrease—even though the plant has taken up more nutrients overall. Sap analysis only measures the concentration in the sap, not the total amount in the plant. Nutrients that are already incorporated into cell structures no longer appear in the free sap.
The better approach: Dry matter analysis
For fertilization trials, I therefore rely on whole-plant analysis with dry matter determination. The procedure:
- Harvest whole plants—for row crops, record the row and plant spacing; for broadcast seeding, harvest small 50 × 50 cm squares
- Determine the fresh weight (FW) and dry weight (DW)
- Measure the nutrient content of the entire plant
This allows the actual biomass per hectare to be calculated and the total nutrient uptake to be derived from it. Only then does it become visible whether a treatment has actually led to higher nutrient uptake—even if the sap analysis shows no difference or even lower values.
Compost Tea – General Information & Effects
Yes, it is very beneficial. Around 70% of the effect of compost tea comes from ingredients such as enzymes, vitamins, and macronutrients produced by the metabolism of microorganisms. Since a pure perlite substrate has almost no organic matter, these metabolic products are all the more important for the plants there.
Molasses is intentionally avoided because sugar can promote the growth of pathogens (harmful organisms) and its viscous consistency makes dosing difficult.
Compost Tea – Production & Technology
This depends on the volume of the brewing system:
- V120: approx. 3.6 liters of compost.
- V500: 15 liters of microbial substrate and 1.25 liters of nutrients.
- V900: 30 liters of microbial substrate and 2.5 liters of nutrients.
- V1700: approx. 50 liters of compost and 4 liters of nutrients.
The optimal water temperature is 20–22°C. At this temperature, the brewing time is 24–48 hours. With colder water (e.g., 10°C), the required brewing time doubles to approx. 48–72 hours.
Yes, but the brewing process will take significantly longer, as the microbiology reproduces more slowly at cooler temperatures. It is recommended to bring the compost to room temperature (20°C) 3–4 days before brewing.
As a rule of thumb: tank volume x 0.6 = air volume in liters. For stainless steel systems, the ratio is ideally almost 1:1.
Compost Tea – Application & Miscibility
3% based on the total amount of water and compost tea can be added.
Yes, boron and molybdenum can be applied together with magnesium in the same spraying pass.
That depends on the product. Chemical wetting agents can damage the bacterial biofilms. Natural agents (e.g., saponins from yucca) are well tolerated. EDAPRO nutrients already contain alfalfa meal, which has a natural wetting effect.
Yes, spray whey can be added at the end of the brewing process and complements the compost tea well.
Nozzles with openings no smaller than 0.4 mm should be used to ensure the microorganisms are not damaged and the nozzles do not clog. The pressure should not exceed 3 bar.
Compost Tea – Storage & Costs
For a V200 system, the microbial substrate and nutrients together cost about 43 CHF per fill.
Foliar Fertilizer – Shelf Life & Storage
The foliar fertilizers have a shelf life of 2 to 3 years without any problems.
They should be stored frost-free and protected from direct sunlight.
Yes, it is recommended to shake the products well before use to ensure even mixing.
Foliar Fertilizer – Miscibility
Yes, most foliar fertilizers can be mixed with each other without any problems.
When mixing calcium with sulfur or calcium with magnesium, miscibility depends on the specific calcium product.
Mixing with copper is not recommended, as it is known that this does not work. Caution is also advised with products like Fytosol (Biocontrol Andermatt), and it is generally discouraged.
It is better to mix them undiluted. In this state, the pH value is lower, which reduces the risk of unwanted fermentation.
Foliar Fertilizer – Application & Dosage
2–3 l/ha is recommended as a foliar application, each in a 1–2% concentration.
Yes, but they should not be too highly concentrated due to the pH value (approx. 5.5). A combination with an alkaline humic acid is advisable to adjust the pH of the mixture to about 6.0–6.5.
Yes, the application of foliar fertilizers can be very well combined with compost tea. In particular, boron (as boron ethanolamine) is better suited for this than conventional forms like borax.
Foliar Fertilizer – Product-Specific Information
- Bio PlantOsol: Purely plant-based, contains amino acids broken down by enzymes for optimal absorption through the leaf.
- Bio NPK (PhytoGreen): Based on corn starch. The nitrogen is predominantly organically bound (proteins, amino acids), with only a minimal ammonium content (0.1–1%).
Downloads
Videos
Compost Tea with the EdaLife in the Netherlands
Adrian Rubi explains and demonstrates his Compost Tea Bioreactor
Compost Tea & Leaf Sap Analysis 🌿 explained by a Regenerative Farmer
Compost Tea Production and Application
Prix Climat Presentation Adrian Rubi
Compost Tea for Golf Turf
Successful Crowdfunding
Winning the Agri&Co Challenge
Presentation Soil Food Web
The Effect of Compost Tea
Scientific Studies
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