Producing growing media in a substrate factory

Peat, the supreme substrate raw material

The main raw material of Kekkilä Professional substrates is first-rate White or Brown Sphagnum peat harvested from our own bogs.

The basic ingredient in the Kekkilä Professional substrates is either White or Brown Sphagnum peat. The peat comes from our own bogs and thanks to the Kekkilä Professional production methods, contains naturally occurring biological active agents.

Organic substrate made by nature

Peat consists of 95 % organic material. It is a mixture of decomposed plant material that has accumulated in a water-saturated environment without oxygen. Sphagnum moss is one of the most common plant species found in peat bogs. Peat, which is extracted from bogs dominated by this group of species, is often described as Sphagnum peat. Sphagnum peat therefore, mainly contains decomposed Sphagnum moss.

Peat formation is a continuous process. Peat typically accumulates in bogs at a rate of 1-2 mm per year.

Peat from the Nordics

The accumulation rate of peat is greatest in areas where the ambient temperature is high enough for plant growth, but where the amount of rainfall, specific topography of the landscape and low transpiration rates cause waterlogging. This limits aerobic microbial activity from breaking down the plant material.

Such conditions are found more frequently in the Northern hemisphere.

Peat – the best growing media for plants

As a substrate constituent peat is superior to any other material when it comes to performance.

Physical Advantages

Sphagnum peat has a high water holding capacity (approx. 65% in volume) which helps to provide adequate water and water-soluble nutrients to the roots. It also has a high air-holding capacity (approx. 30% in volume). The air-holding capacity is important as the roots (and beneficial microbes in the root zone) need a constant supply of oxygen. Oxygen is required by the plant for respiration and supporting the essential functions of water and nutrient uptake. Thus, a perfect balance of both water and air is crucial in any substrate.

Peat has a high cation exchange capacity (CEC). The CEC refers to the ability to attract, retain and exchange cations such as potassium and calcium ions. A high CEC allows a reservoir of nutrients to be held within the substrate and not flushed out during irrigation. These retained nutrients slowly replenish those removed from the substrate by plant uptake.

Because of its ability to hold water and nutrients, peat as a growing media component saves fertilisers and water.

Peat has a low bulk density and is easy compressible. This makes it very fuel efficient for transporting over long distances. This helps to keep transportation costs low and to reduce impact on climate change.

Peat has high structural stability.

Biological Advantages

Peat is produced in remote areas where there is no commercial crop production activity, so it does not contain weeds or other contaminants and it is naturally free of human and plant pathogens, parasitic nematodes, pests and fungi of cultivated plants. In addition, during winters temperatures can dive to below -25 ⁰C which helps to kill unwanted pathogens.

Peat contains beneficial microbes which help to prevent fungal diseases.The naturally occurring humic acids stimulate root growth. It is 100% and as it is an organic material it is also compostable and does not produce unwanted waste. 

Chemical Advantages

Natural peat straight from the bog has a low pH of around 3.5 to 4.5. The consistently low pH allows growing media manufacturers to adjust the pH of the peat substrate depending on the needs of the current crop. Most commercial horticultural crops prefer a slightly acidic substrate. Usually calcium carbonate is added to adjust the pH of commercial growing media to be between 5.5 and 6.

Peat has a low electric conductivity (EC) which makes it easily adjustable. EC is an expression of the amount of salts in a solution. Low EC illustrates that there are very little available nutrients, or other salts – which can even cause phytotoxic effects such as sodium or chloride ions. This ‘blank canvas’ allows the substrate producer to enrich the peat with specific starter fertilisers. The possibility to adjust the amount of specific nutrients accurately is important, because the need for fertilising depends on the type of crops and stage of growth.