I can only speak from my own experiences and also the fact that all my citrus are in large pots.I feed and fertilize (4) times a year which works out to every 3 months.And also when mine are in every phase of growth and have not found this to be true for me.Citrus will drop a certain amount of fruit and leaves as this is their cycle,but certainly not excessive.I have mine on a schedule,here in the Pacific Northwest we do have 4 true seasons and I like to think that mine have adjusted accordingly.They give me plenty of their fruits,sometimes I do have to resort to extra lighting and heat but they do produce well.***Suzanne

Also, yellow leaves can be caused for different reasons. Not enough nitrogen, minerals, over and underwatering, and bugs. What do the yellow leaves look like? Do u have a pic? Toni

My two cents worth= Citrus in the ground are not too fussy.
It is normal for some yellow leaves in the winter time but
can be for the reasons explained above.I have had a meyer in the ground for 5 years,it nearly died but it came back to life.I use a balanced fert n6 p6 k 6 plus trace elements.
The Nitrogen ensures good leaf growth and the fruits reach
their full potential,the Phosphurus feeds the roots and the
k(potassium) helps the flowering and fruiting.However the
trace elements govern the fruit quality.
I have found it very important to feed the tree
late winter and into early spring.This ensures a strong
flowering,then feed half strength every month to change the
fruits from pea size to best size.two to three handfuls for
small trees.little and often.I also vizualize room for the
fruits to grow and thin at least one third of flowers.The
more flowers,the more demands for food.Better have fewer but
quality fruits.I often thin the flowers but you can thin the
pea size fruits too.
Feed occasionally with a soluble fert with epsom
salts(magnesium),that will help your leaves green up.The top
of the leaf should be 3 times darker than below.If your leaves are pale,probably not being fed enough.They are
greedy buggers! I feed my trees every month from spring to
the end of autumn and souluble when i see new growth.
My trees =meyer lemon and satsuma mandarin are
loving it! we get heaps of rain in auckland new zealand.
Distribute fert around tree out to drip line and water in well.I use a fert especially for citrus but make sure it
has the trace elements in as well,makes all the difference.
Also,you could get your kids to pee on them!!!!lemons like
it apparently!!!Good luck

Laidback, let me get this straight? You're saying, pee is good for citrus? LOLOL. What purpose would it serve? I would think urine would harm a plant, just like when a dog wee=wee's on grass outdoors and it yellows? Please expain..Thanks, Toni

Hi, Toni- I don't have any pics and there are just a few yellow leaves, mostly on the lower branches. Overall the tree seems OK, and the fruits are really nice.

Hi laidbackdood- Thanks for your suggestions! BTW, I lived in New Zealand for a while: 2 years in Hamilton and 6 months in Palmerston North. What an incrediby beautiful country- truely Godzone. Your citrus trees are fuller, more lush and more productive with much less effort than ours over here. Bea

Hi,urine is high in urea which is a form of nitrogen.Its
actually a waste product of protein consumption.I dont
actually pee on my own tree!!!but ive heard of people sending
their kids to do it. To be graphic,when the mrs washes my
boys pooey bum(1.5yr) in a bowl of water,i pour that on my mandarin tree!!!making sure the neighbours dont see lol!!!
The mandarin looks very happy.
I have never been to palmy north.The south island is very
stunning but Auckland is over populated.I will post some
photos of my trees when the fruits have sized up,they need
that nitrogen to size up.good luck

I know Mr Jerry Baker, (author) uses urine for gardening..I don't have his latest book but he goes into full detail of its uses.
LOL, I bet you don't allow neighbors to see..hehe
I could have sworn there were threads here on Citrus warning to say away from fertilizers w/Erea. Did I get this wrong? Toni

Hi Toni,I think you are right about advice for not using urea,actually more like millet didnt like to use it,especially
in pots.Its slow acting and relies on soil bacteria to break
it down i think.Not so good in pots but ok in the ground.
I quite often make a liquid manure with grass clippings in a 10 litre buckect of water,grass is very high in nitrogen,leave for a week or more and thats a good tonic too.
All i know,is my clementine gets a lot less sun than
my meyer does,but it gets the pee,poo and grass water.It has
heaps of little fruits at present and leaves look very healthy.both trees are dwarfs.cheers

Laidback, I'm not saying Urea isn't good..I just remember someone writing it in a post or two. I'm sure my fertilizers contain this ingredient..I'd have to read each container to see..
If your citrus are doing well, then continue using the stuff you've been. Cheers, to you, too, Toni