Organic matter is an essential part of any growing media. It is the original slow-release fertiliser. Organic matter improves soil structure and therefore the supply of oxygen and water to plants.

It also regulates the supply of nutrients to the plant by holding them in readily available forms, reduces fertiliser losses in drainage waters and helps to buffer soils against rapid changes in pH. Organic matter stimulates seed germination, root development and general plant growth.

Humus is the stable part of soil organic matter that remains after decomposition. It increases the soil's ability to hold and supply plant nutrients. When humus breaks down, nutrients are released into the soil.

Humus is essential for the well being of soil and its ability to support plant life. The most active parts of humus are the compounds, which have acid properties (humic and fulvic acids). They have the capacity to dissociate hydrogen ions (cation exchange). These acid compounds assist in speeding up the growth of plants by various means.

A good plant growing medium must offer an adequate supply of water and oxygen. Without an optimum supply of both, the plant's growth will be inhibited. In severe cases the plant will die. Too much water, or poor drainage, can lead to water logging. Without sufficient oxygen to its roots, the waterlogged plant drowns.

For good drainage, the growing medium needs to be porous and open, with large spaces between its particles. But water cannot be held easily in these large pores. They drain quickly and then fill with air. The problem with a medium that is too porous is that it cannot hold enough water to prevent the plant's roots from drying out.

On the other hand, if the particle size is too small, while being a great water absorber, the growing medium is extremely poor in releasing it. Quality products release water only as a plant requires, preventing any wastage and ensures adequate supply in times of drought.

Biogreen Peat may also remove the potential of nitrogen drawdown. Nitrogen drawdown, or nitrogen demineralisation, occurs when the microbes that compost the components of potting media use up a plant's nitrogen stores to complete the composting process. This can result in the plant being starved of nitrogen.

The components of a potting mix vary, but generally include, pine bark chips and to a lesser degree sawdust. Nitrogen drawdown will vary between mixes, depending on their various components. Trials indicate that slow-release fertiliser - naturally inherent in Biogreen Peat - will supply the required nitrogen and curb the need for microbes to drawdown nitrogen from the plant.

Plants rely on their growing medium to provide them with the right kinds of nutrients. It is essential that the growing medium is able to supply these nutrients in the right quantity.
All plants are made up of water, carbon molecules (called carbohydrates), and a range of minerals.

The most important mineral is nitrogen (N), then in descending order of importance: phosphorus (P), potassium (K), sulphur (S), calcium (Ca) and magnesium (Mg). Some are cations (positive charge) and others are anions (negative charge).

Nitrogen

Biogreen Peat is particularly high in nitrate. Nitrate is a component of nitrogen, which is the most important mineral because, depending on the type of plant, it constitutes between 1.5 and 4.5% of the plant's make-up. It forms the biggest niche in fertiliser sales with over half a million tonnes sold in Australia per annum.

Nitrogen exists as a gas in the atmosphere. Some plants are able to fix the nitrogen from the atmosphere in to a mineral form - plants are only able to take up nutrients in this purer mineral form. The two mineral forms of nitrogen are ammonium, which is a cation (positive charge), and nitrate, which is an anion (negative charge).

The ammonium form of nitrogen can be toxic to some plants - particularly seedlings. It should be kept to minimum of 50ppm.

Phosphorus

There is a direct interaction between phosphorus and iron. Iron locks up phosphorus in to unavailable forms when phosphorus levels are too high. Because the available iron content of Biogreen Peat is good, the result is suitably lower phosphate levels. This is advantageous to iron inefficient native Australian plants.

Plants remobilise nutrients from older leaves - pulling nutrients from them - and translocate them to the new growing tips. Iron and phosphorus are immobile nutrients - plants are unable to translocate them. A deficiency in either nutrient will be visible in the foliage. In an iron deficient plant, a leaf's vein will remain green, but the tissue between the veins will be pale at first, then yellow, and then white.

If the plant continues to be fed phosphorus, the colour progresses to red. Ironically, one of the main symptoms of phosphorus deficiency in a plant is also redness in the foliage - same symptom - deficiency of iron or excess of phosphate, redness and chlorosis can be easily misinterpreted. In the soil, high phosphate precipitates as iron phosphate resulting in low iron availability.

By adding 20% of Biogreen Peat to a mix there will be an increase in the iron levels of the overall mix and, therefore, control over the available phosphate. Each plant has a different level of tolerance to phosphorus levels.

Potassium

There should be a small amount of Potassium. It should be noted that where the mineral zeolite is present, ammonium should be used to extract the potassium because zeolite holds on to potassium.

Sulphur

Some sulphur should be present. Slow-release fertilisers are responsible for the provision of sulphur.

Calcium & Magnesium

There is an interaction between these two nutrients in that too much calcium causes a deficiency in magnesium, and vice versa.

They are very important elements in a potting mix because most fertilisers don't contain them. The ability of a mix to hold on to these nutrients (or cations) is important so that the roots can exchange them. Magnesium and calcium are base cations that are washed away over time - around six months.

Biogreen Peat contains calcium and magnesium; adding Peat to a mix increases the long-term supply of these nutrients in a mix.