Η ASSEA Bioenergy & Biosoils was founded in 2021 in Kos Island and is the only composting company in the South Aegean region, which produces agricultural products for the healthy growth and maintenance of plants with the main ingredient being the seaweed of the Greek sea, Posidonia Oceanica (the waste of the leaves of the plant that are washed ashore).
Produces and markets unique products Bio Compost ASSEA ® και Bio Soil ASSEA ® , with the aim of significantly improving organic and conventional agriculture. Driven by the circular economy, it is also active in the management of waste and recyclable bulky organic materials with wide action in the private & public sector offering environmentally friendly solutions.

The idea of ​​setting up in Kos, a natural fertilizer production unit using Posidonia marine plants (use of dead leaves that wash up on shores), was born by the founder of the company Apostolia Tsampouniari, Mechanical Engineer, who is specialized and active in the recycling of inert materials since 2010. With the foresight for the need to manage plant (green) waste in the wider Aegean region, the first facility for receiving plant green organic waste (prunings, tree & plant cutting residues, plant residues from the industrial sector, etc.) was implemented for the production of natural fertilizer and soil improvers (high quality humus).

Our philosophy

Our philosophy is based on the production and development of natural fertilizers (mature humus) and soil conditioners (enriched topsoil), from the recovery of "clean" organic waste, with the aim of diverting thousands of tons from landfill, therefore less landfill, lower costs and reduced environmental footprint, strengthening the economy by placing the produced compost on the market, and promoting the tourism product of the Aegean islands as "clean" and "green" islands in accordance with European standards for environmental protection, actively participating in climate mitigation change.


ASSEA products are produced by the process of composting (aerobic thermophilic fermentation). The method we use is open rows (windraws) and our raw materials come from boiled seaweed of the Posidonia plant (Posidonia Oceanica), winemaking stems, olive leaves, olive pit and pure and natural soil.


  1. The ASSEA ® Biological Compost provides plant protection from disease as it is biologically active and contains a variety of microorganisms that have been shown to suppress a number of pathogenic microorganisms such as Pythium, Phytophthora, Rhizoctonia (which cause many symptoms including wilting, root rot and of plant tissue necrosis). By using Compost as a soil conditioner we can suppress these diseases and reduce plant losses.
  2. The Βio Compost ASSEA® replenishes the organic matter of the soil, which is constantly lost to the atmosphere in the form of carbon dioxide CO 2 due to its disturbance and processing, e.g. milling, plowing, etc.
  3. Improves the mechanical composition and structure of the ground, loosens "tight" soils bringing about better aeration, enhances the retention of water and nutrients in sandy and poor soils and encourages the biological activity of soil flora and fauna.
  4. It provides slow enrichment of natural nutrients to plants and thus reduces or limits their dependence on chemical fertilizers. It replenishes the soil's organic nutrients, maintains its health, prevents drying and erosion.
  5. ASSEA ® products contain minimal heavy metals. Our product as a high-quality compost (A+ CLASS COMPOST) is considered free of heavy metals and implies the possibility of its application in double and triple amounts per hectare according to the internationally accepted limits of concentration of heavy metals in the soil for the protection of human health through the food chain.
  6. The Βio Compost ASSEA® has stimulating properties as it comes 80% from the recycling of marine algae that contain a high percentage of nutrients and in particular are very rich in organic calcium and natural growth substances, such as auxins and cytokinins.
  7. The product is organic and comes from a long-term aerobic thermophilic composting process completely controlled, without being "burnt", and characterized by its wonderful very deep brown color (not the carbon black that would be the result of burning), the unique characteristic its texture and its earthy smell (actinomycetes).
  8. The product protects the environment as it does not contain peat since the extraction of peat contributes to the destruction of forests.
  9. Product of full maturation (long-term biological fermentation). The long-term treatment for biological fermentation leads to full ripening of the product, which ensures a non-toxic effect on plants, achieves a high concentration of humic and fulvic acids that favor cell division and better plant growth and ensures the high concentration in flavonoid acids.
  10. Ideal for use in organic farming.


The marine plant Poseidonia the Oceanic, takes its name from the ancient god of the sea, Poseidon. Poseidonia meadows play a very important role in the Mediterranean marine ecosystem and are protected by the European Directive 92/43/EEC (European Habitats Directive).

120 million years ago, Posidonia oceanica covered the coastal plains of an ocean that covered Ecuador. Over millennia they drift with the tectonic plates. Today Posidonia seaweed is only found in the Mediterranean and around the southern coast of Australia.

Posidonia Oceanica lives in a narrow coastal strip between 5 and 50 m deep and is a true plant in the sense that it can bear flowers and disperse its seeds. It plays an important role in oxygenating and creating clear (non-turbid) coastal waters, provides marine habitat for a rich variety of plants and animals, acts as a safe breeding ground for many species and protects beaches from erosion.

Marine algae also play a role in protecting our planet from the increasing accumulation of carbon dioxide, acting as a 'carbon sink', just as plants on land absorb carbon dioxide from the atmosphere, thus helping to slow down the effects of global warming .

Posidonia seaweed has a long lifespan but very slow growth as a marine plant. Over the centuries, the roots form 'layers' that create reefs, which help trap and deposit sediment (suspended particles that cloud the water) and slow the movement of waves, thus cleaning the water and protecting coastlines from corrosion. Dead Poseidonia leaves are stripped from the plants every fall and washed up on beaches.

ASSEA BIOENERGY has an original method of collecting seaweed from the touristic beaches in order to minimize the impact on the morphology and ecosystem of the beach.

ASSEA addresses municipal enterprises (composting of biological sewage sludge), hotels (recycling of organic residues, garden pruning), large agricultural plants, greenhouses and private individuals with bulky organic garden waste and offers comprehensive know-how services and low-cost solutions, for management of non-hazardous organic waste with continuous process monitoring of the production.


  • Seaweed (Posidonia Oceanica)
  • Crowns of Winery
  • Olive Leaves & Olive Kernel


Calcium (Ca) 8-17 %
Magnesium (Mg) 1-1,49 %
Phosphorus (P) 0,7-1 %
Potassium (K) 0,6-1 %
Nitrogen (N)  0,5-1 %


Boron (B) > 650 ppm
Copper (Cu) > 15 ppm
Manganese (Mn) > 450 ppm
Iron (Fe) > 3500 ppm


Organic Matter  20-35 %
C:N  18-25
Conductivity (1:5)  1,03 mS/cm
pH  7-7,8
Dark brown color
Earthy smell


Humidity  25-35 %
Density  ~0,58-0.65 kg/lt


  • It helps in the strong expansion of the plant root.
  • Improves the rate and speed of seed germination. 
  • Enhances the availability of elements in plants. 
  •  Replenishes the organic matter of the soil.
  • Modifies the pH of the soil. 
  •  Significantly increases water retention in the soil up to 6 times its weight. 
  • It increases the porosity of the soil allowing the permeability of air within the soil. 
  •  Facilitates the heating of the soil in the winter months. 
  •  It is free from parasites and germs.
  •  Additional disease control and greater protection by avoiding manure contamination and pest control.

  • Product against soil erosion and drying.

  •  Suitable for reforestation. 

  • Avoid pollution of surface and underground water from the nitrates of chemical fertilizers.

  • Remediation of the soil.


  • Organic Soil natural and clean
  • Bio Compost ASSEA ®, from seaweed from the Greek sea.


Calcium (Ca) 8-12 g Ca/ 100g
Magnesium (Mg) 0,72 g Mg/ 100g
Phosphorus (P) 0,23 % g P2O5/ 100g
Potassium (K)  0,50 g K/ 100g
Nitrogen (N)  0,21 g N/ 100g


Copper (Cu) > 16 mg Cu/Kg
Zinc > (Ζn) 44 mg Zn/Kg


Organic Matter  10-15 %
C:N  25-30
Conductivity (1:5)  0,50-1 mS/cm
pH  7-7,5
Color light brown
Earthy smell


Humidity  20 % – 22 %
Density  ~0,6-0,7 kg/lt


  • Replenishes the organic matter of the soil.
  • Modifies the pH of the soil. 
  •  Significantly increases water retention in the soil up to 6 times its weight. 
  •  Facilitates the heating of the soil in the winter months. 
  •  It is free from parasites and germs.
  •  Additional disease control and greater protection by avoiding manure contamination and pest control.

  • Product against soil erosion and drying.

  •  Suitable for reforestation. 

  • Avoid pollution of surface and underground water from the nitrates of chemical fertilizers.

  • Remediation of the soil.

instructions for use

  1. Put two (2) inches of gravel (or pieces of an old broken pot) at the base of the new pot for drainage.
  2. Add topsoil up to the middle.
  3. We turn the pots with the plant upside down and lightly tap the bottom so that the "ball" of soil from the pot gently falls into our hands.
  4. If there are rotten roots sticking out, remove them with scissors.

  5. Place the plant in the new pot, fill with Bio Soil ASSEA ® plant soil, press lightly with your fingers near the plant and water.

  6.  Finally, on the surface, if desired, add a two (2) cm layer of Bio Compost ASSEA ® around the plant.
  1. Put two (2) inches of gravel (or pieces of an old broken pot) at the base of the new pot for drainage.
  2. We fill the container in a 1:1 ratio, i.e. 1 part Bio Soil ASSEA ® topsoil, to 1 part river sand (optional when sowing in combination with limited use of water-soluble organic nitrogen).
  3. Lightly press the topsoil with a board.
  4. Sow the seeds by hand evenly. The number of seeds depends on the size of the pot or planter and on the type of plant, which needs its space when it grows.

  5. Cover the seeds with topsoil about 1 cm thick, press lightly with a board and water.

  6. We keep the soil fresh by watering lightly at first and daily in a slightly warm environment.
  7. As soon as the new plants sprout, if necessary, we thin out, pulling them slightly.


Seasonal plants: Not required.

All-season plants: We recommend 3 times a year to apply a 3 cm layer on the surface.

ASSEA ® Bio Compost: with the very limited use of a biological nitrogen.


The excellent quality of our products is a primary role of ASSEA and is achieved according to the following factors:

  • 80% seaweed content. The stimulating properties of marine algae (Posidonia oceanica), which make up 80% of our raw materials and their content of cytokinins, favor cell division, for better plant growth.
  • High value content of the product in nutrients, and especially in organic calcium (up to 35%).
  • High concentration of humic and fulvic acids due to the long processing period for the full ripening of the products, they are characterized as non-phytotoxic with all the known benefits resulting from their high concentration.
  • The products have come from an aerobic thermophilic process without being burned, which is evidenced by their wonderful very dark brown color (not coal black), their unique characteristic texture and their earthy smell (actinomycetes).
  • Our product is classified as high-quality Compost (A+) and due to its very low content of heavy metals, it can be applied in double and triple quantities per hectare according to the internationally accepted limits for the concentration of heavy metals in the soil for the protection of health of humans through the food chain. It contains i.e. few heavy metals compared to the best counterparts on the European market (data Wrap June 2022 Waste & Resources Action Program
CHROME 50 mg/kg 70 mg/kg 70 mg/kg 9-28 mg/kg
NICKEL 10 mg/kg 60 mg/kg 25 mg/kg 10-25 mg/kg
COPPER 25 mg/kg 150 mg/kg 70 mg/kg 22-25 mg/kg
ZINC 75 mg/kg 500 mg/kg 200 mg/kg 32-61.5 mg/kg
CADMIUM 0.7 mg/kg 1 mg/kg 0.7 mg/kg 0.2-0.5 mg/kg
MERCURY 0.3 mg/kg 0.7 mg/kg 0.4 mg/kg <0.1 mg/kg
LEAD 65 mg/kg 120 mg/kg 415 mg/kg 4.3-11 mg/kg

Kos: Place of origin of all raw materials from a non-industrial area without problems of acid rain, residual atmospheric pollutants, etc. from clean coasts.


The Organic, Vegetable Fertilizer ASSEA ® Bio Compost comes from the biological fermentation of seaweed (sea plants Posidonia Oceanica) and selected agricultural and livestock products, without any chemical addition or treatment.


Nitrogen (N) 1-2%

Phosphorus (P) 0.6-1.1%

Potassium (K) 2.6-8 g/kg

Calcium (Ca) 20-35%

Magnesium (Mg) 2.00-2.20%

Χαλκός (Cu) 4,6-6,5 ppm

Μαγγάνιο (Mn) 8-16 ppm

Iron (Fe) 120-214 ppm

Zinc 12-27 ppm

Organic substance 30-50%

Conductivity 0.30-1 S/cm

C:N 11-18

PH 7-7,5

Humidity 37-45%

Density 0.60-0.70 kg/lt




It is free from parasites and germs.

Improves the rate and speed of seed germination.

Αυξάνει σημαντικά την κατακράτηση νερού στο έδαφος.

Αναπληρώνει τα οργανικά θρεπτικά συστατικά του εδάφους, διατηρεί την υγεία του, εμποδίζει την ξήρανση και την διάβρωση του.

Modifies the pH of the soil.

It helps in the strong expansion of the plant root. 

It encourages the activity of earthworms and the soil flora and fauna in general. 

It favors the growth of the microbiological population, mainly bacteria and actinomycetes, in the soil.

It helps the bacteria growing in the compost to suppress soil-borne plant diseases thereby reducing the need for fungicides and insecticides. 

It can also work as a plant protection product in the form of the liquid residues of the compost which are usually used as sprays for the leaves preventing the attack of fungi on the aerial parts of the plants. 

Additional disease control and greater protection is achieved by avoiding manure contamination and pest control.

It protects the health of plants, animals and people through the food chain. 

Environmental protection based on the gradual abolition of the use of chemical fertilizers and pesticides, the avoidance of surface and underground water pollution and the protection of flora and fauna. 

High environmental protection based on the philosophy of recycling. 

Energy savings based on the operation of the circular economy which is an integral part of our production process through the safeguarding, reuse and utilization of incoming raw materials