Why are my leaves turning yellow?
I spent several years managing a hydroponics store in
Michigan, and I can’t tell you
how many times a customer
would come in and say, “My
plant’s leaves are turning
yellow. What’s wrong?” I’d
usually stop and take a deep
breath, because I knew I
was going to have to put
my detective hat on! Yellow
leaves can be caused by just
about anything that’s a little
out of whack in a growroom:
low light, overwatering, nutrient deficiencies, nutrient toxicities, root diseases, viruses…
or it could just be a symptom of the plant’s natural
aging process. Who knows?
But when it came down to
nutrient deficiencies, I could
usually narrow it down to one
of three things: magnesium,
nitrogen or iron deficiency.
My first question was always,
“Where did the yellow leaves
start to appear, on the bottom
of the plant or the top of the
plant?” If it was the top leaves,
my prime suspect was iron
deficiency. If it was the bottom
leaves, my first guess would be
magnesium deficiency. And
if it was a general yellowing
of the plant, it was probably
a nitrogen deficiency. I’d ask
a few more questions, just to
narrow things down a little,
such as: “Are you growing in
soil or hydroponics? What is
your pH? What is your EC?
What stage of growth are your
plants in?” Eventually, I’d
make an educated guess and
hope I was on the right track.
Yellow leaves can be caused by just about anything that’s a little out of
whack in a growroom.
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Maximum Yield USA | March 2014