Growing Media
Floral Careers Plant Propagation
Four Functions of a Growing
Medium (Root Medium)
► Provide
a source of nutrients
► Provide a source of water
► Provide aeration and drainage
► Support the plant in the container
Growing Medium Components
and Their Roles in the Medium
Sphagnum Peat Moss
Origin
Decomposed
sphagnum
moss.
Organic or Role in the Medium
Inorganic?
Organic
-Water holding
capacity.
-Acidic.
Composted Bark
Origin
Organic or Role in the Medium
Inorganic?
-Composted
Organic
hardwood and
softwood
barks.
-minus ¼ inch
diameter.
-Improves aeration
and drainage.
-Nutrient holding
capacity.
Composted Yard Waste
Origin
Composted
leaves, grass
clippings and
brush.
Organic or Role in the Medium
Inorganic?
Organic
-Water holding
capacity.
-Nutrient holding
capacity.
Coir
Origin
Organic or Role in the Medium
Inorganic?
Waste product Organic
from coconut
hulls after the
fibers have
been
extracted.
-Water holding
capacity.
-Used like sphagnum
peat moss in the
medium.
-Can be high in salt;
leach before using.
Perlite
Origin
Organic or Role in the Medium
Inorganic?
Volcanic rock
Inorganic
that has been
crushed and
heated to high
temperatures.
-Improves aeration
and drainage.
-Available in different
grades.
Vermiculite
Origin
Organic or Role in the Medium
Inorganic?
Mica-like
Inorganic
mineral that is
crushed and
heated in a
furnace to high
temperatures.
-Water holding
capacity.
-Nutrient holding
capacity.
-Available in grades.
-Coarser grades
improve aeration and
drainage.
Calcined Clay
Origin
Organic or Role in the Medium
Inorganic?
Clay heated in Inorganic
a furnace to
high
temperature.
-Water holding
capacity.
-Nutrient holding
capacity.
Rockwool
Origin
Organic or Role in the Medium
Inorganic?
Synthetic fiber Inorganic
made from
melted basalt,
coke and
limestone.
-Ground rockwool can
improve water holding
capacity.
Sand
Origin
Coarse silica
sand.
Organic or Role in the Medium
Inorganic?
Inorganic
-Adds weight to the
medium.
-May improve aeration
and drainage.
The End