Light levels can also play a role in the darkness of the leaves. With low light levels the plant may produce more chlorophyll and with increasing light levels, less. Think of each chlorophyll molecule as a solar panel on your home. The plant requires a certain amount of energy/food from photosynthesis. If it's getting slightly less than it needs, it will install more solar panels. If it is getting more than it needs, it's not as worried about it and may let some decay and not be replaced.

But let's try this with just one of my citrus..ok.

What should I do to bring this plants leaves to a rich dark green color it once had before?

Please, let's try just one...

It is is full sunlight in my backyard.

My 6 inch ponderosa lemon tree, which I has lost it dark green color within 2 weeks and I am struggling to get that way again...

Should I move it to less light?
Should I feed just FP? For how long without additives?

Should I feed a high nitrogen fertilizer to correct the problem then back to FP?

Like let's say miracid or jacks classic high urea product?

Is urea the trick such as expressed to me at the nursery if temps are suitable?
Miracid?
Then how long should I wait for any one fertilizer to work?
Should I then use iron? If that doesn't work, how about epsom salts?
Then vinegar next step? Get what I mean?
What are the steps to take to make it come back to very green again?
This will be an experiment, and once I see a difference,hopefully quickly, then I will finally apply this tecnique to my other plants. I will use the same fertilizer and regimand for all..
This I have been struggling to do for years. My plants are growing though.
Please, some one work with me on this.
I would like to start as soon as tommorrow on this plant.
I will take a pic of before and after..
By the time I figure it on my own, it just may up dead!
I think many here might benefit with the heads of the brains behind this forum or specific thread together.
Here, sure, there is a lot of facts as to plants needs, but no results on the very problem some have with just facts. How about instructions?...
Turning our leaves to a DARK green.

Please help me unless this is an impossible feat...

Thanks very much!;-)

Fine, I will give you a suggestion:

Get yourself some liquid chelated iron fertilizer and use that along with the FP. I really doubt your plants need this, but it will likely give you the darker leaves you are after.

Then we can all be happy ;)

Again no one has the ability to help me reach this goal.

I asked for someone to help me step my step with just one plant, and still nothing.
So today I gave it a dose of Iron, now that it is in a warm enviroment again. Next I will feed it Miracid. Then next Jacks Classic 20-20-20 with urea, then next epsom salts, then next vinegar. If it dies by the time summer is over...Oh well.
If anyone one desires to help me make just my one ponderosa a beautiful dark green, I will work with ya...
Here is my e-mail.. Once occomplished, I will send you payment... mikerno_1@yahoo.com
No expectations....:-)

Thanks for helping in other ways though!!:-)

You are really appreciated!!;-)

I have been thinking about your questions and I want to ask you some of my own.

In particular, what is the weather like in your part of zone 5? In my part days have been 45-80F and nights 40-60F. My citrus are all outside, but none are growing much, if at all. It's just the weather.

Last spring I ordered my first 3 citrus. They arrived healthy enough, but it was really cold out so I kept them indoors for a month or so and then put them outside. The leaves weren't at all dark and some were mildly chlorotic. I aksed about this on the citrus forum and the advice I got was it was likely weather related. It was simply not yet warm enough for citrus to assimilate nutrients and grow well.

Sure enough, once decent summer weather arrived everything looked good.

So, I overwintered them indoors and they did fine, but the meyer started dropping some leaves toward end of winter. Probably the lack of humidity.

Then I ordered a couple orange trees that I potted up about 3-4 weeks ago. These are also outside now. Very light green leaves, but not chlorotic and no new growth yet. Again, it's the weather.

So, what I am saying is consider the time of year and the weather/humidity.

I don't think adding a small amount of iron is going to harm anything, but please also consider that indoor or outdoor, zone 5 isn't ideal citrus territory. Certainly it can be done, but I don't think it's reasonable to expect the same performance from them, at least consistently as a grower in Florida would get.

For me...I tried something a little different. I've had my Meyers Lemon for almost four years. I've had issues with
Citrus leaf miners, but that's a different story...I've had mine outside in full sun 24 seven. Recently, I've noticed that the leaves were not as green even though I fertilized it on a regular basis. I've had it sitting on my Patio cement(no roof), so it gets sun from sunrise to sunset, 360+ days a year. I decided appx. 5-6 weeks ago that maybe my container lemon was just getting too much FL sun, that the container was just roasting especially being on the cement and the sun just bakes it all day long. We've been in the upper 80's to low 90's for the past 8-10 weeks. I decided to move it under my FL oak trees, where it gets direct sun from 7am to noon and mostly shaded(little filtered sun from the trees). Also, I've had to water this tree every day when I had it on the cement/all day sun...Well, apparently it prefers this protection from the blazing afternoon sun, it has since greened up and bloomed, I have several baby lemons and more blooms are appearing. I'm also watering it a little less often. For me at least, I guess full sun doesn't mean 8-10 hours of full spring/summer FL sun! I guess it needs a little shelter during the hottest part of the day. I know that your weather is much different than mine, but thought I would just share my experiment.

BTW, as JAG suggests, I also use Chelated iron every 4-6 weeks during the spring and summer and alternate Miracid, then MG...I ran out of Foliage Pro.

Here's a picture of my tree...it may not be as green as the nurseries...but greener than what it used to be. I've also noticed this on my Hoyas, some varieties when it gets too much sun, it turns pale, gets yellow, washed out looking, which is what JAG pretty much said, if I understood it correctly,lol

What's the update? Have you tried anything to get teh leaves greener?

Thye are all starting to look really medium green! I will take a picture and let you be the judge.Maybe I was too critical of them, expecting to much from them, knowing what they once looked like when I first brought them home. Especially the ones I got from "Four Winds"
I think they look alot better, now that there is no yellowing leaves, especially on the new growth.
You are right, I fully agree with you, these areas are not that hospitable to keeping them as healthy as they are in the south..
The weather here has been staying above 50 now except for a day or two at evenings, and the days in the 70's.
Also, just as you said, Iron might help, well it sure did within days!! I mix Iron into my fertilizer regimand. NO vinegar though. So, now, who knows, could be either the iron, or the warmer weather, or the Peters fertilzer 15.30.15 with urea for a quick fix...lolololol
But they look greener. Just not the DARK green as before, when I first bought them. I could see the dark green getting lighter and lighter until what I have now.
I will send pics of the dark green leaves turning lighter of the citrus I had just recieved fron four winds, and how the leaves looked after a few days as I was referring to, and you will see what I meant.
Hey at least they are not yellow right? Can't ask for everything...
Can we all be happy now?..Lol
You are the best man!
Mike