Growing Media and Quality why peat

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Growing Media and Quality why peat?

• Gerald Schmilewski
• Lamoura, France, 8-11 Oct. 2007

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• Presentation outline
• Definitions
• Overview of materials
• Choice of material
• Materials used in the EU
• Prospects for GMC in the EU

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A few definitions Growing media Material,
other than soils in situ, in which plants are
grown. Growing medium constituent Material
that is suited as an ingredient of growing media,
generally admixed on a volume basis.
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Growing medium additives Additional
ingredients, added to a mix on a weight
basis. Soil improver Material added to soils
in situ, mainly to maintain or improve their
physical properties and might improve their chem.
and biol. properties.
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Growing medium constituents
Pre- shaped
Composted materials
Peat
Inorganic materials
Other organics
Bog peat 1-5 Bog peat 6-10 Fen peat 1-10
Bark Coir Wood fibers Wood chips Rice hulls Others
Bark Wood Biodegrad-able waste Green waste Others
Perlite Clay Exp. Clay Sand Vermiculite Lava Pumic
e Others
Mineral wool Foam Others
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The plant Sphagnum
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W.A. Casparie
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Choosing the right Growing Medium
GM producer Mr. Nurseryman
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Choosing the right medium/constituent

• Physical
• Structure and stability
• Water and air capacity
• Bulk density
• wettability

• Chemical
• pH
• Nutrient content
• Buffer capacity
• Harmful substances

• Biological
• Weeds
• Pests and pathogens
• Other microbes
• Storage ability

• Economical factors
• Availability
• Quality consistency
• Plant requirements
• Price

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Why is Peat the main GMC throughout Europe?

• Peat combines more favorable
• chemical
• physical
• biological and
• economical
• characteristics than any other GMC !

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• What does the choice of a GMC depend on ?
• Intended use
• Chemical, physical, biological characteristics
• Availability (local, regional)
• Acceptance (by producer, grower, end user,
  public)
• Price (raw material, processing, transport)

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• Prospects for GMC in the EU
• Reduce, recycle and reuse biodegradable waste
• More use of composted biowaste in GM (mainly
  hobby)
• use only in mixture (high pH, K, bulk
  density)
• Quality assured GMC are vital
• Peat remains most important GMC
• Reduction of peat extraction in some countries
  increase
• in other countries
• Mineral materials are not peat alternatives
• No more synthetic materials
• Not peat-free but more peat reduced

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Sphagnum papillosum