Agriculture Reference
In-Depth Information
FIGURE 5.12 Milwaukee portable 3-in-1 pH/EC/TDS meter. (Courtesy of
Milwaukee Instruments, Rocky Mount, North Carolina.)
the changes in EC with certain elements that consistently get used up more
than others. Then you can carry the solution longer by making periodic
additions of these elements based on the changes in EC readings.
SYMPTOMS OF NUTRITIONAL AND OTHER PROBLEMS
If your plants are receiving not enough or too much of any element they
will show symptoms of yellowing (chlorosis), browning (necrosis), defor-
mation, or stunting of growth. For specific descriptions, functions of ele-
ments within the plant, and determination of nutritional disorders, refer to
my topic Hydroponic Food Production . Here I only want to point out some
generalities to assist in recognizing nutritional problems with your plants.
Be aware that diseases or insects may also cause symptoms of spots and
chlorosis. The first thing to do is to determine whether the symptoms are
on the lower or upper part of the plant. The essential elements are grouped
as those that are mobile, which can be retranslocated, and those that are
immobile, which cannot be retranslocated (moved) to another part of the
plant. If they are immobile the first symptoms will appear on the upper part
of the plant. Mobile elements express their deficiency on the lower part of
the plant as they move to the new growth leaving the lower leaves to suffer.
Often fruit formation may be affected at the same time. For example, one
of the most common symptoms is blossom-end rot (BER) as shown in
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