The choice of material that comprises your growing media will
probably be the most important decision you can make in growing
a superior cycad. Proper fertilizer is important, but a poor growing
medium can render even the best fertilizers virtually useless.
Organic materials that are commonly used to make up potting soil
in Florida are: Florida peat, Canadian peat, pine bark, and saw
dust. To increase drainage, people use very coarse sand, chicken
grit, pumice, Perlite, Airlite, Zonolite, and other similar products.
One thing that many people fail to realize is that most everything
involved with growing plants breaks down to chemistry and physics.
When choosing a component for your soil, not only do you look
at what the material is now, but what it will become later. Florida
peat will very quickly turn into muck. Growing cycads in muck
is probably the worst thing you can do. PH is also very important.
Pine bark as it breaks down will turn your soil very acidic. The
chemistry between your soil and fertilizer breaks down with very
high or very low pH.
Pine bark, if not aged for a sufficient amount of time, can leach
out as much as 50% of the nitrogen in your fertilizer. It also
seems to be a magnet for ants, cockroaches, and termites.
Florida peat is made of organic materials that have broken down
over many, many years. All the trees, bushes, and other small
plants in a certain area die, then break down and settle in a
depressed area. After thousands of years, this becomes a peat
bog. Any nursery person can tell you that most plants are susceptible
to their own particular insects and pathogens. Peat derived from
several species of plants may also be susceptible to just as many
pathogens as the plants themselves. Canadian peat is primarily
broken down sphagnum moss. Not only does Canadian peat not break
down as fast as Florida peat, but it also does not seem to be
as susceptible to disease.
I originally used a standard nursery mix of 50% Florida peat and
50% aged pine bark. Then I would add coarse sand to that mix.
Depending on the cycad species I was potting up at that time,
I would add sand so that it made up 20% to 50% of the total mix.
Central American Zamia would get 20% sand, whereas Encephalartos
horridus or E. arenarius would need 50% sand. After that, I would
add about 10% to 20% Perlite. Even though that all worked very
well, I was having problems from time to time with fungus, especially
with seedlings. Also, not having a uniform mix caused problems
with watering. Some of the plants were getting dry too fast, and
some were staying too moist.
One day I went to Kurt Decker's nursery and looked at his soil
mix. It was made up of 40% Canadian peat, 30% coarse sand, 20%
cypress saw dust, and 10% Perlite. After seeing seedlings that
we had purchased at the same time, and realizing that his were
larger than mine, I thought I would try his mix. After using this
mix for three years, I have seen great results. The plants root
faster, I have not had as many problems with pathogens, and it
is a uniform mix I can use for everything. Also, because it is
Canadian peat based, it breaks down slower, and I don't have to
re-pot as often.
My problem was that my original soil mix cost about $14.00 per
yard, whereas the new mix is about $32.00 per yard. The former
owner of 1-4 Plantland, Don Maynard, used to tell me, "The
most expensive thing you can buy is cheap soil." To illustrate
this point, he explained that he had purchased two loads of "bad
soil". After about a year, he threw away $75,000.00 worth
of azaleas. For those of you who say you can't afford $32.00 per
yard, let's look at this monetarily. The difference between the
two soils in cost is $18.00 per yard. Most people can fill 250,
one gallon pots per yard. If you are growing rare species of Zamia,
even if you lose only one plant out of 250 because of cheap soil,
which is the better choice? I would also venture to say you would
lose a lot more than just one plant, on the average. Losing ten
plants could pay for a ten yard load of good soil.
Through the years, I have always had problems with the "parazamia"
type of Macrozamia. For the last four years, I have been growing
Macrozamia in pure coarse sand, with a small amount of regular
soil in the bottom of the pot. If you just use sand, it will pour
out the bottom of the pot when it gets dry. Since I have been
doing this, I have not lost even one Macrozamia. It is important,
however, that you use a complete fertilizer like Nutricote, because
sand obviously has no nutrients.
Along with fertilizer, the type of soil is the most important
variable for growing a healthy cycad. The only other variable
is water, but that is a subject for another article. When the
chemistry between your fertilizer and the soil is working well,
you can then use advanced nursery techniques to manipulate your
cycads to grow faster, and to produce more seeds, as well as reduce
your plant mortality rate.
