I've not been happy with the results I've been getting with my current feeding regimen utilizing water soluble fertilizer. I've been using Grow More's soluble Citrus Food. The NPK ratio is 20-10-15. The nitrogen breakdown is 4.9% ammoniacal, 2.9% nitrate, and 12.2% urea. I don't know the biurit content. The minors include 0.5% magnesium, 3.5% sulfur, 0.01% boron, 0.05% chelated copper, 0.2% chelated iron, 0.08% manganese, 0.0001% molybdenum, and 0.1% chelated zinc.

Many of my trees are more chartruese than deep green. Those trees which have the darker green leaves also tend to exhibit significant chlorosis at the tips of last year's leaves. I suspect some of this is a root cultural problem. Last year, before I bought my own house, I had all my trees on white rock in a side yard with zero shade. In spite of all the warnings by more experienced participants on this forum, I think I managed to inflict considerable heat damage to the root systems of most of my trees. By the end of summer I had seen considerable leaf drop. Yes, sometimes the trees were watered daily when the ambient temperature was ~95F of above, but I don't think the root damage was due to overwatering. If anything, I think I let them get a little too dry at times.

This spring everything started to green up with the initial application of fertilizer in late February. That application consisted of 2 tsp. per gallon of water. That was followed by applications alternating between 1 tsp. and 0.5 tsp. per gallon at 2 to 3 week intervals. Most of the trees were left on my new deck under a shade canopy. The deck faces west with the canopy sandwiched between the house and the back fence. The trees on the south side get direct light. The others are shaded by the house in the morning and the canopy screen midday and afternoon.

As the season has progressed, most of the trees have been slowly yellowing. I moved my Tarocco orange to a spot in the yard where it would get direct sun most of the day, including the container. The move only seemed to accelerate the chlorosis and leaf drop. In late June I moved five of the younger trees (Pixie, Valencia #1003049, Dancy, Cara Cara, and Algerian Clementine) and placed them along my southern fence, situating cement blocks between the plants to shade the sides of the containers. This combined with an early July application of 1 Tbs. per gallon has led these trees to green up and produce only the second growth flush of the year. My Lisbon lemon and Bearss lime are located such that they get direct sun for a good part of the day. This requires me to water these plants more frequently than most of the others, but again, I allow the soil to dry several inches in depth before watering. These haven't flushed since March/April. I moved the Tarocco back under the shade screen sometime in June. That stabilized the chlorosis and leaf drop somewhat. The stronger application of fertilizer last month has begun to green up many of the younger leaves and produce a very limited growth flush, but I'm seeing more pronounced chlorosis of the slightly older leaves.

Four other trees (Corpaci lemon, Olinda Valencia, Ortanique, and W. Murcott Arfourer) have soil induced root problems. All four are from Willits and Newcomb. I've kept them in the original sandy soil too long. The soil compacted. In late June I repotted the lemon and Arfourer, both of which have stabilized in terms of leaf drop and are now flushing mostly blossums, which I am pinching off. I need to repot the other two.

Most of my potting media is very free draining. I believe this combined with a too dilute regimen of my water soluble fertilizer has led to nutrient deficiency from leaching. A week ago I fed everything at 1 Tbs. per gallon and followed that up this past weekend at 1 tsp. per gallon. I plan to continue the 1 tsp. rate weekly through August, with one last application at the 1 Tbs. rate around September 1st.

For next year I am considering switching to a slow release fertilizer. In particular I am looking at Safer Brand's Lawn Restore. It has the optimal NPK ratio for container citrus of 5-1-3 and no urea. Its composition is as follows:

Quote:

Guaranteed Analysis Total Nitrogen 10% 1.9% Nitrate Nitrogen 0.5% Other Water Soluble Nitrogen 7.6% Water Insoluble Nitrogen Available Phosphate (P2O5) 2% Soluble Potash (K2O) 6% Derived from: hydrolyzed poultry feather meal, nitrate of soda, potassium sulfate, bone meal and soybean meal.

To this I would add a micro supplement, either STEM or something like Safer's Granular 15% Iron Plus.

Quote:

Guaranteed Analysis By Wt. Calcium (Ca).............................4.5% Sulfur (S)..............................10.50% 10.5% Combined Sulfur (S) Iron (Fe)................................15.00% 14.75% Water Soluble Iron (Fe) 0.25% Chelated Iron (Fe) Manganese (Mn)........................0.75% 0.75% Water Solule Manganese (Mn) Zinc (Zn).................................1.50% 1.5% Water Soluble Zinc (Zn) Derived from: ferrous sulfate, Gypsum, iron EDTA, manganese sulfate, zinc sulfate.

What do the chemists/ag science types on the forum think about the proposed new fertilizer?

Kent

The game changes when we want to grow our Citrus
outdoors in containers as opposed to indoors in a
greenhouse. For much of the fertilizers for outdoor
Citrus, both in ground and in containers we have to
experiment a little and the 5-1-3 ratio may not apply
to us based on the predominant soil type we have for
the in ground trees and also for the potting mixes we
use for the container plants.

Also, when making a decision on how much fertilizer
to use and when to apply it we also need to take into
consideration that lush green growth in a warm climate
may not produce as much fruit as a mid shade of green
leafed plant will. Too much Nitrogen for in ground and
container plants can affect the amount of flowers we may
see and hold on the tree later as an example.

Different sources have different issues that cause a
chlorosis to be seen. We need to be more conscious
of which type of chlorosis are we seeing and what
nutrient deficiency or even a nutrient toxicity is
causing it. The latter may seem outlandish to some
people but applying Ferrous sulfate to a container
plant and not giving it enough water can in fact create
much more chlorotic symptoms than we had before
we applied the Iron. Chlorosis on the old leaves does
not bother me here with plants in containers in full
sun in 100 degree temperatures but new growth with
a Manganese chlorosis showing as the leaves are
emerging and while starting to expand will cause me
some concern. I'd be more alarmed seeing this in the
in ground trees however.

A lot depends on the rootstocks we have on our trees
which so few people want to talk about. The dwarfing
rootstocks have a little more trouble absorbing nutrients
than a standard rootstock will. We may have to apply
more fertilizer, more often, to the dwarfing forms than
we have to for the semi-dwarf and standard forms because
of it. Then again some of the rootstock forms do not
have lush green leaves to start with when allowed to
grow on and become trees for taking cuttings from
to be used as a rooted cutting rootstock was what we
saw in the nursery. Troyer and Carrizo do not produce
as lush a green growth that a Washington Navel will
here, all things being equal, either in containers or in
ground. Some Mandarins are not known for being a
real rich green in leaf color anyway. Some Lemons
are the same way and other forms of Citrus as well.
Some of the Citrons never really do green up well
in some of the warmer and drier climates.

The problem with container plants when we want to
fertilize and apply minors is that when we deep water,
such as hose watering, we flush much of the nutrients
right out of the container. This is why some of the
liquid injection methods for fertilizing are preferred
in some areas, especially when the trees are watered
by sprinklers or with drip type systems.

We always have to be mindful of what is going
on with the roots. When we see plants lose newer
growth leaves and it was not the result of heat or
intense sun all we need to know is that the roots
are not happy. We've seen many threads in the
UBC BG Citrus forum of people asking why is
my Lime losing its leaves or why is my Lemon
dropping its leaves [most of the time all of the
questions involve container plants], we can
assume that the roots are not pleased with us
in the soil mix we've given the trees, how much
water or lack thereof we've given the trees, and
when the trees were fertilized not enough water
was given to the trees. We've seen evidence in
a few recent threads whereby most people have
referred to giving the tree too much water when
by the looks of the soil we can tell that there
has not been enough water given to the tree
that caused the leaf loss and the discoloration
to the leaves. When people talk about a white
colored salt deposit on the drainage holes, we
should not assume they know for a fact that
those deposits are salt when we see no signs
of salt buildup on top of the soil or right at
the soil line inside the container. We do have
areas that have lime in their water which can
cause the deposit on the drainage holes and
no one seems to ask or inquire about that.

The age of the tree does make a difference to
me also in that it is better to have 2-7 year
old trees show the effects of nutrient deficiency
rather than a 10 year old tree. We can correct
deficiencies easier with younger trees but most
people fail to tell us what we need to know to
better analyze what is wrong with their tree.
Even to the point of not telling us something
that may have caused the whole problem.
All we can do is band-aid their situation when
they refuse to tell us what they did or did not
do to cause the problem they are in so-called
dire need of having an answer for.

Another thing is that each Citrus grower nursery
has their own nutrient nemesis but we have to
learn what those issues are the hard way. We
do not equate what can go on with W&N trees
with Four Winds or Ivanhoe Citrus or Menlo
Growers, or C&M and others. They each have
their own issue with their trees. Some of
the issues are masked when we buy the trees
and will see the leaf issues later after we've
had the trees for a year. I will comment now
that the Willits & Newcomb trees I've had
come in immediately get repotted into my
hand mixed potting soil. Then again many
of their trees I've had already had roots hitting
the bottom of the cans and when we lift them
out of the five gallon containers we can see
that they are ready to go into a fifteen gallon
or into the ground, almost at the time we get
them. When we leave them in the same can
for any length of time we suppress their
growth potential. I have found that their
trees, not all of them, like my rich humus
soil a lot. The four Italian Lemons from
them just love it, most of their Mandarins
do as well. Then again for us my soil mix
that we use may not apply for everybody
and therein is the crux of the problem that
what works for me may not work the same
in Watsonville or for you where you are or
for people in South Carolina and Texas. We
all assume that what works for certain areas
in Florida applies to all of Florida and that
is simply not the case at all. We go with
what we've got that is different than everyone
else and we make adjustments accordingly.

We do not normally apply Ferrous sulfate
or Gypsum to an acid soil. Sometime read
up on why that is in the Western Fertilizer
Handbook. We've had the same discussion
in the The Maple Forum recently. There are
several parallels that the Maple people
are facing that many of you in Citrus do
as well. There have been times this forum
was referenced for the members of the
Maple forum to look in and read some of
the informative posts that are in this forum,
some of the Maple people are members of
this forum as well because of it.

Jim

Jim, you have hit on many important points. I have always believed a nutrition program that is used on containerized trees is much more demanding,and requires greater caution, than for trees planted in the ground. Citrus trees growing in the soil are not all that finicky of what fertilizer is used, as long as the tree's nutritional requirements are met. I would venture to state that the top three areas of importance in good container tree culture are: 1). the root system, 2). the root system and 3) the root system. For container trees, 95 - 98 percent of the problems that develop are problems inside the container, not in the scion. As for container trees grown by nurseries, I hold to the rule that the nursery must either sell the tree by the first year, if not sold then transplant the tree into a larger container, or plant the tree in the ground , or throw the tree away. Lastly, the probable reason that insufficient information is traditionally given when a container grower is asking for assistance with a problem being experienced by their tree, is because the grower himself/herself does not understand what is going on, and therefore is unable to sufficiently explain what is actually taking place. Anyway Jim, good post.- Millet

Jim,

Thanks for the feedback! (Ditto Millet) I'm very glad to see you are still monitoring this forum and posting. I remember another thread not too long ago where you expressed frustration and pondered the value of continued participation. At the time I didn't get around to saying how insightful I find your posts.

I was afraid my original post in this thread was too verbose, but I'll try to provide additional information as to my cultural practices that could be affecting my trees. This weekend I'll also try to provide pictures, allowing those of you more experienced than myself to assist me and others in learning to better interpret the condition of my trees. I understand the key to successful citrus is a healthy root system. The challenge is in learning how the different factors involved interplay with one another.

I suspect one reason I am having difficulty diagnosing my cultural faults, is that I'm seeing a combination thereof. Root damage caused by excessive heat and allowing the potting media to dry too much probably contributed the most. My reason for specifying that four of the trees are from W&N is that the soil used by W&N is significantly different from what 4W and C&M use. It was obvious to me that the W&N soil had compacted to the point it was adversely impacting root health. On the two that I've repotted so far, I had to work considerably at rinsing the soil out of the root ball. I'm certain my persistence contributed to additional root hair damage in the short term, but should be better for the tree in the long term.

My potting mix varies somewhat depending upon availability of components. The Valencia #1003049, Dancy, Cara Cara, and Pixie are all from C&M. I replanted each last year from 4x4x16 liners, so they're all 2-3 years old. The mix I used at that time consisted of 4 parts fine fir bark (RM Wonderbark), 2 parts loamy potting soil (low peat content), and 1 part perlite. The same mix was used to repot the Tarocco from Menlo and the Lisbon from either Menlo or 4W, also last year. The Algerian Clementine, also from C&M, is in the original nursery potting soil. These are probably 3-4 year old trees, as are I presume the W&N trees. The Bearss lime came from 4W. I've had it almost 3 years, so I would say it is 5-7 years old. It was potted in straight, run-of-the-mill potting soil and I plan to repot it this next spring. Not previously mentioned are four other trees, a Page from Menlo and a Meyer, Moro, and a Owari Satsuma from 4W. They appear to me to be the healthiest of the lot, excepting that the Page is battling a bout of gummosis and the Meyer suffered heavily last year from hot roots. When I repotted the Corpaci and Orlinda Valencia this summer, I couldn't find the same soil used in my original mix. The closest I could find had less sand and more peat, plus some perlite. So my new mix ended up becoming 4 parts fine fir bark and 2 parts soil mix.

My concern about sticking with my current water soluble fertilizer is the 12.2% urea content. I couldn't find any information on the manufacturer's website as to the biuret content. Should I not be too concerned about the urea?

I'm still digesting the information from Vol. 2, Chap. 3 of The Citrus Industry. If my problems are related to leaching, however, it sounds like switching to a slow release organic form of nitrogen, such as Safer's Lawn Restore should be beneficial. The down side is I will need to be careful of sodium levels. Also, am I correct that this formula by itself will not assist in maintaining a slightly acidic soil? Any additional thoughts on the suitability of this particular product? And thanks for the caution concerning ferrous and calcium sulfates in the 15% Iron Plus supplement. You are right, I didn't take those into account.

Kent

It can be difficult for a hobbyist to learn what rootstock a nursery used for a given varietal. Anyone know what rootstock the following growers use?

Four Winds: Bearss lime, Meyer, Owari Satsuma, Moro, Lisbon
Willits & Newcomb: Corpaci, Ortanique, Orlinda Valencia, W. Murcott Afourer
Menlo Growers: Tarocco, Page
C&M: Pixie, Valencia #1003049, Dancy, Cara Cara, Algerian Clementine

Don't ever worry about overwriting. When people post
we get a better idea as to what they know and in your
most recent post what all you have for Citrus. This
becomes real important as much of the time some of
us can tell who will be in Citrus for the long haul and
who will be out of the game in a manner of a couple
of years. We see it a lot in Maples whereby someone
is gung ho until they get stung a few times and then
they just disappear. A few setbacks always will turn
people off and much of the time it was because they
chose not to study what they were getting involved
into. If we have an idea what the plants needs are
before we bring it in to grow on we can deal with
issues we may later face a whole lot better than
bringing in a Mexican Lime blind with fruit on it
and by the second year of having it see the plant
start to falter and then worry about what to do for
it then.

Frankly, the mixes you are wanting to use should work
well for you but for a 15% Iron this is better used for
in ground plants than for container plants unless we
go to a half strength application. I played with an idea
to mix some Miracle-Gro Citrus Shake and Feed with the
all-purpose Dynamite Plant Food and see what that does
on some of my container Citrus here. Then if I see
some results to my liking we may use it on the
misses container Citrus 60 miles down the road from me.
The main reason I've used a 0-10-10 fertilizer for Fall and
late Winter/early Spring applications for most of my
other plants is that I want some nutrients in the soil
before the deciduous trees leaf out. Once in leaf
I'll give them some Nitrogen then.

I have my way of growing Citrus in containers here of
which I am "running" against conventional wisdom all
because I want to try to get an established root system
on our plants before we expect too much from the trees.
I really do not want a lot of fruit the first two years I
have Citrus come in (all have been 5 gallons) and will
concentrate on building up the root system to enable
the plants to better adapt for my location, including a
concrete RV pad in full sun at the misses home that
for now has to occupy some of the Citrus as we've run
out of room to put the cans on bare ground. We have
no intentions of planting the Citrus in her yard which
is currently overplanted with ornamental trees, shrubs,
accent plants, Maples and Magnolias among other things.

Below is a pamphlet you should be able to get or order
from your Sonoma County Cooperative Extension Office.
The price is $10 or use the link with cookies enabled to
order it from ANR.

California Citrus Rootstocks

http://anrcatalog.ucdavis.edu/InOrder/Shop/ItemDetails.asp?ItemNo=21477

Below is a link to the CREC site that has a link to their
rootstocks. Now if only IFAS carried the Nutrition of
Florida Citrus Trees, I'd buy a copy of it also.

CREC Publications for sale

http://www.lal.ufl.edu/publications/pubsale/sale.htm

Jim

Posted: Thu Aug 09, 2007 2:15 pm Post subject:

--------------------------------------------------------------------------------

Kent, to find out what variety of roots stocks your trees were grafted upon, just telephone 4W, CM and WIN and ask them. I have called suppliers many times asking what the root stock are, whenever I receive a tree and the root stock is not listed on the label. It is much better gauging the concentration of a fertilizer solutions using parts per million (PPM), than using teaspoons and tablespoons as your guide. As far as the Safer Fertilizer I would never consider using such a fertilizer. There are MUCH MUCH BETTER nitrogen sources to choose from than Nitrate of Soda and chicken feather meal, better sources of phosphate than bone mean. Soy bean meal???? In my opinion, of the currently available slow release fertilizers on the market, Osmocote is the top of the line. Citrus has always had a difficult time producing with organic fertilization. I believe your tree will face problems using an organic fertilizer with a 10-2-6 formula where 76 percent of the total nitrogen is insoluble, thus unavailable to the tree. Have you looked into what the soluble salt index of such a product would be? It is your tree, you can give it whatever type of care you wish, but you asked for others advise. A good nutrition program is a combination of a slow release fertilizer in conjunction with a water soluble fertilizer. Whatever, I wish you and your tree the very best of luck in the future. - Millet

Fertilizers obtained from organic compounds
work better in some soils than others. For
container trees if we have lots of humus with
some native soil in our mixes then the organics
are not a problem for us. Much of the time we
have to determine do we want a slow release over
a period or time or do we want a quick release,
to have some benefit right now. I like residual
for container plants which is why I am more used
to using commercial granulated fertilizers than I
am liquid forms. I do not use organics per say
for container plants but for the in ground plants
I have been known to till in forest humus to aid
the soil composition by adding in organic matter.

I've always felt that occasional applications of
Cottonseed meal has helped our in ground Citrus
in Tulare County with a Hanford series clay loam.
Some people want the nutrients in the meals to
help them, I want something other from the meal.

When asking about a growers rootstocks they
are using we may have to be more definitive
on which plant we have from them and is it a
semi-dwarf, dwarf or a standard. The W&N
trees that we have, have color coded markings
on the tree and the rootstock. Knowing those
colors coded patches may come in real handy
when asking them what rootstock they used
for their Ortanique, Orlinda Valencia and the
Afourer [a quick note on the Afourer, I saw
a few 5 gallons of thiers this year marked
W. Murcott with the Afourer absent. The
first W. Murcotts sold that I know of were
not the Afourer. Most all of them are now
however].

Jim

Jim, I think we are in agreement on 98 percent of the discussion. I am not anti-organic. I think organic culture has it place, but I believe its place in not inside the container of a containerized citrus tree. For trees planted in the ground, one can do what ever a person desires. However, even when an in the ground citrus tree is nourished only by the organic method it never produces a crop that can be expected when using standard methods. I agree with you a little addition of cotton seed meal or whatever to an in ground tree from time to time could be an advantage. I have nothing against using organic treatments, along with standard methods. Anyway, Jim I have always truly respected you knowledge- an especially your on hands wisdom. Whenever Jim send me an E-mail, the interest it generates in me, leads me to an hour or so of investigating, I have learned a lot. I always look forward to your E-Mails. Take care. Kent can proceed in any manner he wishes. Millet

I wholeheartedly agree that organic solutions
for container Citrus by themselves is not a good
method for sole fertilization. We both have seen
comments from people in the Pacific Northwest
advise others to use organic meals, even liquid
emulsions, as their primary fertilizers and I just
cringe when I read that for edible crops such as
a backyard Peach or a home garden Apple. I
thought the use of organics in this case were to
be mixed in with something else or used as a
supplemental.

We both know of a regimen being used whereby
the primary fertilizer is a granular form and the
secondary is Osmocote. For that particular site
I like what they are using. Essentially the Miracle
Gro mixed with the Dynamite All-Purpose plant
food would be my secondary or supplemental
fertilizer to my granular applications.

Another thing that is more true for me that when
I feel the need to add Iron and Zinc for in ground
trees and the container plants when need be also,
I am more accustomed to using a foliar chelate
spray than using a ground based application.

Jim

Again we are in agreement. The method that I use for the correction of iron, zinc and sometimes manganese deficiencies is a foliar chelate spray. However, trace minerals are also added to the growth medium as a supplement with the fertilizer. My favorite fertilizer method is Osmocote 17-6-12 with trace minerals incorporated in the growth medium as a constant slow release base of nutrition, along with a soluble liquid fertilizer twice a month. One of the best things about a good slow release fertilizer program, is the fact that the nutrients are there and available and the plant does not have to wait until the grower gets around to fertilizing. I think I need to try your granular fertilizer as a trial on a tree as you suggest. - Millet

Yes, Osmocote gets replaced by surface application when needed. Another good formulation is Osmocote 19-6-12, but 19-6-12 does not contain trace elements, therefore if 19-6-12 is used the trace minerals must be applied separately when needed - Millet

Thank you Millet, Sonoma, Snickles.

I have noticed a significant decrease in fruit production since switching from conventional(non-organic) fertilizing. I have a full jar of osmocote that I've simply not used. I did not fertilize for three full months last winter and I believe that that was also part of my problem.

I have been using fish emulsion and compost tea to feed this season. I have noticed much new growth, but a reduced yield.

If the length of my posts equates my knowledge of the subject, then my bevity speaks for itself. I could speak VOLUMES about my passion for growing citrus. I'm in this for the long haul. It is nice to have a place to go to learn more in our quest to understand the secret lives of our trees.

Thanks again for sharing your knowledge.
Scott

My concern about sticking with my current water soluble
fertilizer is the 12.2% urea content. I couldn't find any
information on the manufacturer's website as to the biuret
content. Should I not be too concerned about the urea?

I thought the biuret content was more important for foliar
applied Urea than ground or in this case container applied
applications. I was not aware that fertilizer companies
were all too concerned about the biuret content in ground
based programs.

I may have to check this out but here is where I'd start
if I did try to find out more.

Jones, W. W. 1954. Biuret toxicity of urea foliage sprays on
Citrus. Science 120:499-500.

Impey, R. L., and W. W. Jones. 1960a. Rate of Absorption of
urea by intact leaves of Washington navel oranges.
Proc. Amer. Soc. Hort. Sci. 76:181-85.

—— 1960b. Effects of biuret on nitrogen status of Washington
navel and Valencia orange leaves.
Proc. Amer. Soc. Hort. Sci. 76:186-92.

The nice thing is that we can take the title of such an article
and copy and paste it right into a Search engine such as
Google or WebCrawler and then see where it leads us.

I'll give away a secret now. I've found several old Hilgardia
(the University of California Journal of Agricultural Science)
topics recently [spent some real time trying to organize and
catalog the article names by the year they were published
and the volume number] and then plug the article header into
a Search engine and see if those articles are online or not.
If not, then in some cases I've been able to find some
expanded, more recent articles in which the particular
article I was looking for was used as a reference. I have
found a couple of old Hilgardia articles that have been
reprinted online as well but more of them are not online
yet. I had some fun with this one below last evening
which led to me what the symptoms of a biuret toxicity
look like from the University of Florida, IFAS Extension.

Jones, W. W., T, W. Embleton, M. J. Garber, and C. B. Cree.
1967. Creasing of orange fruit. Hilgardia 38:231-44.

Jim