Frequently asked questions

Peat moss

Sphagnum is a genus of approximately 380 accepted species[2] of mosses, commonly known as “peat moss“. Accumulations of Sphagnum can store water, since both living and dead plants can hold large quantities of water inside their cells; plants may hold 16 to 26 times as much water as their dry weight, depending on the species.[3] The empty cells help retain water in drier conditions.

Sphagnum have a distinct structure adapted to the watery habitats which they live within. The water acts to support Sphagnum plants, meaning strengthening structures are not required. There is: Capitulum: an uppermost rosette which is engaged in photosynthesis. Main body: consisting of a stem and branches. Bottom: Sphagnum are unusual in that the lowermost parts of the plant are dead and decomposing.

A large difference between Sphagnum and other mosses is in the pattern of branching seen. Sphagnum have a main stem from which branches are emitted. Stems and branches are covered with photosynthesising leaves. These vary in shape between species and help identification.

Decayed, dried sphagnum moss has the name of peat or peat moss. This is used as a soil conditioner which increases the soil’s capacity to hold water and nutrients by increasing capillary forces and cation exchange capacity – uses that are particularly useful in gardening. This is often necessary when dealing with very sandy soil, or plants that need increased or steady moisture content to flourish. Anaerobic acidic sphagnum bogs have low rates of decay, and hence preserve plant fragments and pollen to allow reconstruction of past environments.

Peat volume

The metric volume is what you were used to; a certain (fixed) cubic capacity, for example a lorry. Potting soil delivered in metric volume can be delivered with fluctuating density. The metric volume cannot be reproduced within the company and not between different suppliers. This especially becomes clear when is switched over to another recipe, at which during potting sometimes shortages or remainders arise.

The substrate industry needed a method with which the volume could be determined
unequivocally and repeatable. This has resulted in a European standard method

Performing the method EN-12580, one uses a cylinder with a content of 20 litres
which is filled in a standard way. Due to this method, the cylinder will be filled as
homogeneous as possible. Filling the cylinder in this way is reproducible. The weight related to the volume of the cylinder leads to the measure for the (fresh) bulk density or bulk weight. The data on volume and weight have reference to the production location.

At potting soil companies often automated measuring technology has been installed in the production lines. This measuring technology has been based on the reference system with the EN-cylinder. The weight of the total freight is determined. The total weight divided by the bulk weight leads to the number of EN- m³ of the concerning shipment or delivery.

The Association of Potting soil producers in The Netherlands (VPN) and RHP have executed practical research to determine the practical value of the EN-volume. In a test setting with a potting machine, both large as well as small pots have been filled with various mixtures. The test demonstrated a clear relation between the content of a loosely filled pot and the EN-volume. The contents of a 1-litre pot equals, as a rule of thumb, with one litre EN-volume (loosely filled, levelled, not pressed).
The additional potting soil which is brought in the pot when pressing, determines the extra volume used. The level of compression can be determined by weighing the pot.

The volume delivered by the substrate supplier is expressed in m³, formerly in metric volume and nowadays in EN m³. The switch to the method EN-12580 can lead to a change in the delivered number of m³. Dependent on the recipe and the current properties of raw materials variations occur in the number of delivered EN- m³ of substrate of 0 % to more than 25% increase compared to the former
metric volume. Changes in raw materials and/or recipe can lead to a change in the potting behaviour of the substrate. This may result in more or less density in the pot, and more or less consumption of volume. Weighing the pot content and
relating this to the bulk weight will provide clearness about the required EN-volume.


Biofuel, any fuel that is derived from biomass—that is, plant or algae material or animal waste. Since such feedstock material can be replenished readily, biofuel is considered to be a source of renewable energy, unlike fossil fuels such as petroleum, coal, and natural gas. Biofuel is commonly advocated as a cost-effective and environmentally benign alternative to petroleum and other fossil fuels, particularly within the context of rising petroleum prices and increased concern over the contributions made by fossil fuels to global warming.

Liquid biofuels are of particular interest because of the vast infrastructure already in place to use them, especially for transportation. The liquid biofuel in greatest production is ethanol (ethyl alcohol), which is made by fermenting starch or sugar.