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THECOMMERCIAL GREENHOUSEGROWER • MARCH 2018
• GROWINGMEDIA
drive comes fromgrowersmaking their ownminds up
about the ethics of continuing to usepeat, or if they have
aparticular customer such as theNational Trust that
demands that plants are grownwithout peat,¹ explains
CatherineDawson,Melcourt’s Technical Manager. ¸Many
of our customers aredoing very goodbusinesswith the
National Trust which is expanding their plant offer.
¸The technical pros and cons of peat versus non-peat
arebeing studiedby project CP138but this iswork that
we had todo years agowhenwe startedproducingpeat
alternatives,¹ she continues. ¸Most growers don’t have the
time or inclination to change theirmanagement practices
greatly sowe set out to ensure that our peat-freeproducts
could slot intogrowers’ current systems very easily. There
are slight differences – but nogreater than thedifferences
that can alsobe foundwithinpeat-basedmedia.
Aswell as the environmental andpolitical reasons for
addingothermaterials togrowingmedia, there can
bepractical and technical advantages too. ¸Many
growers are now seeing thebenefit of addingpeat-free
components such asWest wood fibre into their growing
media, with regards to thequality and shelf life of the
plants producedwith theseblends,¹ saysMark. ¸These
peat reducedmixes actually provide superior performance
to traditional highpeat basedgrowingmediawith a
number of benefits such as air-fill porosity andwater
management.¹
At the same time, there are some signs that asmedia
attentiononpeat reduction has decreasedover recent
years, so too has thedemand for peat-freeproducts
from some sectors. ¸For us, the interest inpeat free and
peat reduced substrates, and requests to supply them
in theUKmarket, have reducedover thepast five years
or so, despite our continuous investment inmachinery
tomanufacturewood fibre andother constituents, whilst
also financingongoingR Dwork intomore alternative
materials,¹ saysHermannKonnemannof German-based
Klasmann-Deilmann. However, he feels that the 25Year
Environment Plan is likely to see interest rising again.
¸Around65per cent of the growingmedia usedby the
professional horticulture industry comprises peat" this
represents about 0.72million cubicmeters of peat across
horticultural markets,¹ saysDr Eleni Siasou, technical
manager for growingmedia at ICL. ¸It will take time to
switch topeat freemedia on a large scale. Peat remains
the only growingmedium that has been extensively
studiedby soil scientists and thus its properties are fully
known and understood. Themajority of plants thrive in
peat-basedmedia includingpot andbeddingplants.
Growers are experienced and confident at growing their
plants inpeatmedia and in themanagement in terms
of irrigation, nutrition, EC, AFP andgeneral horticultural
practices.¹
Hermann alsopoints out that increasing the use of
peat-freemediamay actually increase horticulture’s
environmental footprint in some other areas: ¸Certain
alternativematerials topeatmay requiremore irrigation,
at a timewhen freshwater conservation is being
encouraged.More fertilisationmight be requiredwith
certain alternatives and this in turn requires the use of
fertiliserswhich carry an additional footprint.¹Concerns
are alsomentionedon competition for wood-based
products, such aswherepossible competition from the
energymarketmight inÅuenceprice or availability in the
future.
¸Until growers becomemore convincedof the long term
availability, consistency, cost andperformance of the
alternativematerials, then conversion topeat free or peat-
reducedproductswill remainbelow its full potential. This
could inpart also tobedue todissatisfaction in theway
that previous attempts to address the use of peat have
been conducted. The recently developedResponsible
SourcingCalculator allows peat tobe comparedwith
alternatives on fair basis, and highlights the fact that
alternatives topeat also comewith adverse impacts. It’s
still in its infancy, but withon-goingwork couldgainwider
acceptance.¹
Fewer growers nowmix their ownblends of growing
media, whichgivesmanufacturers greater control of the
end result andwhich, in turn, increases confidence in
rawmaterialswhichmay be included. ¸There are very
fewgrowers left whomix their owngrowingmedia,¹ says
KlasmannGreenFibre.
Ultramodernproduction facility toproduce highquality
substrates 1iffy products .
