 Fertilizing Trees
by Daryl Bessell
METHODS OF FERTILIZING TREES IN THE FALL
Any complete fertilizer that is high in nitrogen and potassium but low in phosphorus is useful for trees. A fertilizer with numbers like 30 10 30 could be used. Trees can be fertilized in the fall about the time the leaves fall and the application should be no more than half the total annual application. Choosing the best method to apply fertilizer will
depend on what is growing under the tree, the soil conditions, the amount of time and labour available and the specific nutrients required.
a) Surface application with dry fertilizer - spread
required quantity of fertilizer uniformly over the
tree root zone and then water the area well. The
zone of actively absorbing roots begins several
meters beyond the drip line (outermost branch
edges) and extends toward the trunk approximately
two thirds of the distance between the dripline and
the trunk.
b) Hole application with dry fertilizer - holes are
made throughout the actively absorbing root area,
approximately 1meter apart, about 40cm deep and
at least 4cm in diameter. Distribute the
recommended amount of fertilizer among the holes.
Some tree-care professionals mix an equal amount
of dry sand or organic matter with the fertilizer
before filling the hole, allowing 5 cm at the top for
topsoil. Water the area thoroughly and repeat at 10-
14 day intervals thereafter if necessary.
c) Hole application with liquid fertilizer - a
fertilizer solution is forced into the soil by means of
a root feeder that consists of a perforated, hollow
rod attached to a source of water pressure. This
method has the advantage over surface applications
of not over-stimulating grass or other plants
growing under the tree. The feeder rod needs to be
pushed into the soil to a depth of 6 cm and no more
than 30 cm and at intervals of about 1 meter.
(2011-03-13) |
