Here's a question more out of curiosity than anything. In the last couple of years when I've shopped around for citrus, I've noticed there's quite a few out there that have a lot of yellow leaves on new(er) growth. On the mineral deficiencies listed on Mr. Citrus' website it appears that a sulphur deficiency produces such results. Is this a common problem or is there something else that causes the yellowing? It seems like a commercial grower would correct any mineral deficiencies so that he/she has a good looking product on the market.

Phillip

The main problem is that during cooler weather, nutrient uptake is minimal. Thus you would always see some yellowing and a lot of nutrient deficiency like symptoms on Calamondins, lemons, kumquats during the winter. The kumquat especially

Here's a question more out of curiosity than anything. In the last couple of years when I've shopped
around for citrus, I've noticed there's quite a few out there that have a lot of yellow leaves on new(er)
growth.

Let's break this down a little. Was it a specific grower's Citrus that had yellow leaves showing
on the new growth or are you seeing the yellowing common to all of the growers Citrus for sale
in your area? I am not sure the same growers plants are available to you in the San Diego area
as they are to us here in the San Joaquin Valley. Most of the plants we will see in the mass
merchandizer retail outlets such as Lowe's and Home Depot will be Four Winds, Willits &
Newcomb for five gallons and on occasion some younger plants from C&M nursery. The
retail nurseries will generally have Four Winds, Ivanhoe Citrus and on occasion Willits &
Newcomb mostly in five gallon sizes. Most of the time we cannot compare what a plant
looks like in a Lowe's to a retail nursery as the Lowe's want to move these plants in and out
quick whereas a nursery can have these plants sitting on the ground for retail sale for two
seasons and longer.

It is when these plants have been setting around the nursery, being hose watered that they can
indeed start to show some nutrient deficiencies as much of the nutrients that were in the soil
mediums have been flushed right through the container, leached out in time due to the super
saturation watering techniques used at the nursery. One of the above mentioned growers has
been using a gelatin coated fertilizer that serves to release nutrients over time much like
Osmocote does in that they are timed released fertilizers. Once in the retail nursery I doubt
many of these trees have been fertilized at all. Some trees from one of the above growers are
known to be in stock at certain retail nurseries for three to four years and not be fertilized once
by the retail nursery. We can expect those plants that were not richly colored when they came
into the nursery to start with to yellow out on us. In this specific case not due to a Calcium
deficiency but to a deficiency to a host of nutrients. Then when we try to correct for this
allover yellowing we end up giving these trees too much Nitrogen which for them does the
opposite of what we want, in that the trees will not grow much and will not color up as well
as we want them to. We have found just give them new soil and watch them color up a little
and then come in with a series of non N, P, K, nutrients with granular and later on liquid
forms of fertilizer and these trees will color up nicely for us here.

Yellow leaves does not tell us much, as most people equate what we feel is a chlorosis as
being a yellowing of the leaves. We see this a lot, much more often than seeing an allover
yellow leaf. When we see a chlorotic leaf we think in terms of Manganese, Magnesium
and Iron deficiency. When we see an allover yellow leaf we think in terms of Calcium
and in some cases a Nitrogen deficiency. If we see an allover yellow leaf in which the
new growth is noticeably smaller in size than the old growth we are thinking we have
an advanced Zinc deficiency. Sulfur deficiency is more of a general term as we can
come in with a Manganese sulfate, Magnesium sulfate, Iron sulfate, Calcium sulfate,
Zinc sulfate. If we look at the labels of our fertilizers we can see the makeup of the
constituents on those labels and we may also see our primary Nitrogen source came
from Ammonium sulfate. So, we can determine that in most granular fertilizers for
Citrus, Sulfur will be in the fertilizer formulation in some way. If we do see a bona
fide Sulfur deficiency and for here this would be an extreme case, would lead us to
believe that someone has not been fertilizing those trees at all for some time. Certainly
if they want to balk at that notion, then they have not been using a complete or a
balanced fertilizer for their Citrus in a long while.

Most Citrus that we buy in containers do not have a high percentage of soil in those
mixes. One thing that most people do not realize that nurseryman learn on their own
is that depending on the soil mix used by the grower, where we have these plants either
out in the open or under shade cloth that our watering can flush the nutrients that were
in those artificial soil mediums right out of the can rather fast once they come into the
nursery. So, we should be a little more objective of what we are seeing when we see
some of these plants that have some yellowing of the leaves, as we should try to
determine which leaves, old or new or both and is it common for that grower source
to produce plants for resale that have some deficiency and soil issues with their
containerized plants and is it something that has been habitual in that for a few
years now we have been seeing the same chlorosis problems in the new and old growth.
Then we have to decide whether we really want to own that growers plants or not or
look for plants that we will feel better about buying from another source instead. If
the plants do not look good to you or you cannot determine what their problem is or
might be, then do not buy them.

Snickles

Plants coming into the nursery outlets and the retail nurseries
this time of year may have some yellowing due to cold but
this is not common for plants that are being outlet now that
had been grown or stored for a few months in a greenhouse.
Most outdoor container growers here in the San Joaquin
Valley or the inland areas near San Jose would not bother
to try to sell their Citrus now to retailers. Not all of the
"yellowing" we see is due to lack of nutrient uptake and
sap flow now, a good portion of the yellowing is due to
lack of stored nutrients in the plants system. If we gave
our container trees a late Summer and early Fall fertilizer
with no Nitrogen in the last application, we may not see
any chlorotic or allover yellow leaves at all on the new
growth now on several forms of our Citrus. All yellow
leaves on our plants right now should be old growth
leaves that are about to be sloughed off soon by the
plant anyway. It is rather typical of most Lemons,
some Oranges, more so true of the Blood Oranges
and some of the Mandarins to do this right now after
a small bout of freezing low temperatures we are now
having. The newest growth that we just got and are still
getting on our Mexican Lime, for example, is far better
for color than it was all through the Summer. The plant
is sending out some blooms at the moment also. It
bloomed last year for us at this same time of the year
as well. Dad said he will give this tree its first Nitrogen
dose since we've had it (April 2005) next Spring.

Snickles

First, I would be EXTREMELY surprised if the leaf yellowing is caused from a sulfur deficiency. Visual symptoms from sulfur deficiency are extremely rare. Also it can't be to cold being in San Diego. I agree with Jim that the two best possibilities for the leaf yellowing are, old leaves being discarded from the tree (right time of the year), or container trees that have set in the nursery and that have been watered over and over, thus leaching out all or most of the nutrients from the growth medium. - Millet

Phillip, is there any chance of you knowing who the grower
or growers are of the Citrus you saw? You do have some
Citrus growers located not far from you that can sell their
plants to the nursery sources you mentioned.

There have been some leaf issues we've seen on Citrus as
they were coming into a Lowe's and some Home Depot's
mostly in other areas that we saw last year, so we are not
discounting what you saw as we've seen some chlorosis
issues with some of those plants. It would be rather
unusual for some of the nurseries that Snickles mentioned,
although not out of bounds depending on when, what time
of year the retail stores got those plants in. Solid yellow
leaves and/or chlorotic leaves would be extremely rare
to see from one of the nurseries Snickles mentioned
as their plants always look lush and are a rich green in
color when they come into the retail outlets. Otherwise
those plants generally do not leave that growers nursery
until those Citrus have some color to them. That does
not mean that the color will stay or hold up for months
on end but mass merchandiser resellers are expecting
those plants to move out the door within days, thus they
will not be around long to develop any real discoloration
to the leaves. A Lowe's or a Home Depot cannot sell a
chlorotic or yellow leafed Citrus too well. They end up
having to discount them hoping people will take a few
of them home with them or they may end up "eating"
them, not getting any money back from the resale of
them.

Jim