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Robert
M. Pirsig in his classic “Zen and the art of motorcycle maintenance” alerted me
to how as our society has evolved, even some of the simplest tasks in our lives
have become beyond our comprehension due to the advance of technology or the
bluff that surrounds basic functions threatens us. I feel this regularly in the
garden too.
The
notion of being an organic gardener is a wooly image. At what stage do we cross
the line? Does the using of light miscible oils compromise us? Using “blood ‘n
bone” may seem a great organic additive, but what does it really do for your
soil and your plants? There are so many conundrums, but let’s look at ‘your
friend and mine’ old blood and bone.
Fact
one.
The only nationally available blood & bone that is what is says it is, is
the Gardening Australia product made for us by Perryman’s in Victoria.
There
is very weak organic legislation in most states and territories about what can
be sold as blood and bone. In NSW the organic component does not even have to
be animal meal, let alone blood meal or bone meal. It can even be 5% canola
meal or linseed meal, bulked up with sand or gypsum or any other non organic
product. Most jurisdictions permit at least 60% filling matter, that is usually
sand in the mix and very seldom is blood or bone meal used due to the price at
present, but usually animal meal, including all the fats. That’s why water runs
off most “blood ‘n bone” product when watered.
Fact
two.
Much of the nutrient that is contained in most complete water-soluble
fertilizers is locked up and not available to your plants, due to your soil pH.
This
is not an indictable offence; it’s just that making targeted fertilizers for
each region in this country would be too expensive. It does however mean you
would be better off to use your nutrients more carefully. For instance I live
in a region with high salinity in the soil and in the reticulated supply, so
using water-soluble fertilizers that leave a lot of unused salt residues does
not make good sense. Also the alkaline nature of Adelaide’s clay soil and many
similar soils in NSW, means that the elements and associated compounds such as
iron, zinc and manganese get locked up and are not available, no matter how
much you use. These nutrients can be applied as foliar sprays and the problem
is immediately overcome. Similarly on quite acidic soils the elements and
compounds of calcium, phosphorus and nitrogen get locked up. With the exception
of nitrogen, these are not so easily applied as foliar sprays.
Fact
three.
All plant nutrients are absorbed or taken up by the plant only in solution with
water.
This
is true even of underwater sea grasses and desert plants that may only grow
once every 10-20 years. This is why maintaining soil moisture in the growing
season is so important, for all plants. I stress in the growing season. Palms
and many indoor plants go dormant in the cool of southern winters and any
attempt to keep them watered or fertilized will result in great stress and even
death. Another corollary of the soil moisture Zen, is that when you buy a 6
month controlled release fertilizer prill product, it means that in the
presence of water and a soil temperature in the range of 12-25 degrees C, that
product will release in about 6 months. However if you use that prill in a
container in full sun where pot temperatures in summer can be 30-45 degrees it
will release its nutrient in just 6 weeks! Leave your pots to dry out and sure
they stop releasing nutrient, but when you resume watering there is a build up
of salt that can often be far in excess of what your plants will tolerate and a
brown margin appears at the edges of your plant leaves. We call this salt
induced toxicity. There are a few ways to contain the damage though. Kelp and
seaweed extract products are widely used in commercial horticulture for this
purpose and ironically to reduce the damaging effects of frost also.
There
are many other truths in gardening too just as there are in Zen and I invite
your questions or for you to share your findings with us.
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