Most fertilisers are manufactured from natural products that are either mined from natural deposits or made from the air we breathe.  Of course, in most cases these basic raw materials are further chemically treated, fortified or processed to produce the common fertilisers that most farmers will recognise.

In some cases, the raw unprocessed minerals can be used as fertilisers with the permission of the Soil Association provided certain conditions are met.  Here are just a few of the fertilisers that Bunns keeps in stock and can be used in organic farming systems.

Sulphate of Potash

Sulphate of Potash is approved for use by the EU and can be used for organic systems with prior notification when the Potash Soil Index is less than 2. Sulphate of Potash is a particular suitable potash source for irrigated or saline soils such as is found in glasshouses or under plastic tunnels. Using Sulphate of Potash can also give higher dry matters in potato crops, which makes it suitable for crisping varieties.

The chemical analysis is 50% K₂O water-soluble potassium oxide (41% K) 45% water-soluble sulphur trioxide (18% S) and is available as a granular fertiliser suitable for 24m spreading.

Granular Kieserite

Granular Kieserite is the common name for magnesium sulphate and is approved for use in organic farming in accordance with European Commission Regulations EC 2092/91 and 1073/2000.

Granular Kieserite is processed from Powdered Kieserite, which is itself separated from Kainit, another organic fertiliser.  It contains 15% [25% MgO] magnesium and 21% sulphur [52.5% SO₃]. The magnesium in Kieserite is completely soluble and available at all pH's [unlike calcined magnesite].It is a fast-acting fertiliser for use where readily available magnesium is required.

Kainit

Kainit is a naturally occurring ore, EU-approved for use in organic farming and is approved for use in organic farming in accordance with European Commission Regulations EC 2092/91 and 1073/2000 by prior consent containing

• 11% K₂O water-soluble potassium oxide (9% K)
• 5% MgO water-soluble magnesium oxide (3% Mg)
• 29% Na₂O water-soluble sodium oxide (20% Na)
• 10% SO₃ water-soluble sulphur trioxide (4% S)
• Plus many other trace elements.

Kainit is particularly suitable for sugar beet, carrots & grassland production.  Routine fertilisation of grassland with Magnesia-Kainit improves the health, productivity and fertility of grazing animals by enriching the forage with magnesium and sodium.  Kainit should not be used on potatoes, where the sodium content will cause crop damage.

Patentkali

Patentkali has been classified as being suitable for Organic farming systems according to EU regulation 2092/91 and it has recently received certification from the Soil Association as a fertiliser suitable for use in organic farming systems (approved & restricted).

It contains 30% Potash (K₂O) + 10% magnesium (MgO) + 42% sulphur (SO₃) and is virtually chloride free for crop friendly application with all nutrients in the water soluble sulphate form for top quality produce.

Rock Phosphate

Natural rock phosphate is an unprocessed phosphate ore that is used as the base-material for Triple Superphosphate production.  The phosphate is relatively insoluble, especially in alkali soils with pH > 7.5, so should be considered as a rotational fertiliser.

All of the farms certified by the Soil Association must have production systems that plan to minimise the need for any brought-in nutrients; however, with permission, farmers can use these fertilisers where soil analysis has shown severe deficiencies. Under the Soil Association's guidelines, farmers must demonstrate an agronomic requirement and permission will be granted provided to use the fertilisers if there is suitable justification for their use.

If the farmer finds severe deficiencies, with permission, they can use the following supplementary nutrients; boron, copper, iron, manganese, molybdenum, cobalt, selenium, zinc, sodium (in the form of granular rock salt).

These fertilisers are held in-stock by Bunns and are available for immediate dispatch.