[Terrapreta] Uses of Charcoal in Horticulture and Gardening. British article.

[Michael Bailes]

*Uses of Charcoal in Horticulture and Gardening.*

Charcoal has been used for horticultural purposes for at least two thousand
years,

archaeological research has come up with evidence of charcoal being used as
a soil

ameliorator in the Amazon basin around the time of Christ. (Do a web search
for "Terra preta" for more information)

Green keepers of golf and bowling clubs used charcoal extensively as a top
dressing but

in recent years this has been substituted by sharp sand, the reason may have
been that

the demise of the British charcoal industry caused a shortage in supplies of
the correct

grades. Fine charcoal powder used on lawns (golf) absorbs and eliminates
excess

amounts of fertilizer and chemicals present in the soil

.

Charcoal was widely available from horticultural sundriesmen up until the
late 1960's,

for use mainly in bulb fibre where the pots do not have drainage holes. The
charcoal was

said to keep the compost 'sweet'.


Orchid growing employs the use of charcoal and specialist growers of *
carnations* and

*pinks* find charcoal to be invaluable.

Research has shown that growing mediums that have charcoal present, are able
to buffer

the effects of sporadic watering, by reducing the frequency of watering
whilst helping to

prevent 'damping off'
*Charcoal also reduces the leaching of fertilise in free draining soils as
the charcoal's porous carbon structure enables the nutrients to be held for
slower release to the plants *
.

*The inclusion of charcoal in open seedbeds showed that it facilitates the
uptake of*

*nutrients.* Calcium uptake almost doubles, with significant increases in
potassium,

magnesium and phosphorus, the pH increases slightly and there is an obvious
increase

in organic matter.



Charcoal has been recommended as part of the treatment for the eradication
of a fungal

disease, Cylindrocladium that infects Box hedges.

*Charcoal has proved to be an ideal renewable substitute for perlite and
vermiculite,*

compost additives used to increase aeration and aid drainage, but both
finite resources.

*The currently favoured water retaining gels are not liked by all growers*

*and there are doubts about how well they actually release the water they
have absorbed *"Petunias in

hanging baskets tested in greenhouses showed no benefits when
water-absorbing

polymers were used. And plants grown in media containing water-absorbing
polymers

required watering just as often as plants grown in potting soil containing
no water-

absorbing polymers. Also, their usable life is limited by the amounts of
salt or fertilizers

in the soil

*". Hence, charcoal could be used where watering may be a problem, *e.g.

*hanging baskets, or where it is hard to change the compost, e.g. in large
tub*s.

Charcoal could be incorporated into locally produced 'green compost'. No
further

processing, other than simply grading would be required and transport costs
would be

low. We have had preliminary discussions with Scarborough Borough Council
about

adding fines to their Green Compost and they hope to do some simple trials
in hanging

baskets.

*The full article is here*
http://scholar.google.com/scholar?hl=en&lr=&q=cache:I0TgdV-gQ_UJ:www.visitthemoors.co.uk/uploads/publication/978.pdf+



-- 
Michael the Archangel
"Politicians will never solve The Problem;
because they don't realise they are The Problem.".
-Robert ( Bob ) Parsons 1995
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