Post pics, describe feeding and watering, make sure pics include the potting soil.

Watering: soak when fully dry. Soil has a lot of stones and stuff mixed in for good draining.

Feeding: gave iron last year hoping it would help. Nothing else lately.

It's probably hungry, the soil looks very dense, you might want to remove it all and replace with new that's mixed 50/50 with perlite.

also stones don't help with drainage at all.

Well it is about 50/50 perlite own but it's been a year since I repotted. Repot again? Should I prune anything on top or in roots?

When I used to grow pot I used 50/50 perlite and potting soil, as kindly as I can say it, that looks nothing like the stuff I used to use. The white perlite should be everywhere.

If your confident that the soil drains fast then just feed it and see what happens.

Please don't re pot just yet!!! Hold off...You can do other things to save it and not send it backwards until it's the best time to re pot.

Pip has a good eye..That mix is very dense and it's easy to tell

Okay so it's too dense but I shouldn't repot. What should I do then? And when should I repot?

I would flush the mix out now that it is outside..I would use a hose and freely let clean water run through it for a few seconds...Water the whole tree, give it a good shower.

Do you have any access to potting soil, mulch prefferably, a larger pot than that one?

I would also start using vinegar with a stronger dose of fertilizer...What do you use may I ask?

Giving it iron is not going to work if your roots are not happy either because they are too wet for too long, dying off from salt deposits, not use to the temps outside, or if the pH is off....If your fertilizer already has iron in it I would first try what I suggested..May I ask, does your fertilizer contain Iron? Have you checked the pH of your fertilizer solution?

The best time to re pot is when you see active growth come about the beginning of June depending on where you live. In that state, I would not risk it if you can try other things first...

If the soil is soaked it doesn't matter how much water is ran through it. The general consensus at least with cannabis growers is you have to use 5x the containers volume of water to properly flush the soil due to the cation exchange capacity cec of the soil.

at that point you feed it a weak feeding to give it something to eat.

Im still worried the roots are dying from suffocation and only a lighter mix will fix that.

If that soil has salt deposits, flushing it does make a HUGE difference...I would flush that mix out and I would not do a soil exchange unless you plan on doing a bare root which will stress that tree even further...When a tree, especially citrus in in bad shape like that, a bare root at the wrong time will almost always kill it.

The roots will not suffocate if you you do a thorough flush and die off from salt deposits, so since it is outside, it should dry out even quicker than if cooped up indoors...

Once those salts are gone and the soil is cleaned, once you start using vinegar and use a good fertilizer as Pip mentioned, and once it adjusts to the warm sunny days and not so cold nights, it will become very active..Once it's stronger and you see it responding well, the you could do a full bare root and have little negative impact on your tree....If you do not plan on a bare root, it makes no sense at all to use a different soil since two different mixes never work together , other than the same bad one you are using, which will cause you future issues..

Just a side note...

Ideally, AT LEAST 15-20% of the water you apply in a single watering will exit the drain hole. That's how we usually flush the soil when we water. If you can't water that way w/o concern your soil will remain saturated so long it affects root function and health, you probably should look deeper into figuring out what you can do to ensure you can water correctly. The ability to water correctly also sets you up so you have close control over your fertilizer supplementation program. Close control means you know that all nutrients plants normally get from the soil are in the soil and available for uptake at a ratio that doesn't present problems and a concentration high enough to prevent deficiencies yet not so high it makes it difficult for the plant to take up water. With a good soil and a good fertilizer, achieving that end is no more difficult than watering. W/o a good soil, achieving that end is difficult in the extreme. Using a good well aerated mix which is what you will use soon, will give you many possibilities)

15-20 percent every time you water. But if you haven't been and the salt is built up you have to do the 5x the soils volume to get the salt out.

cation exchange capacity means that the soil will chemically bond with nutrients and you have to use a lot of water to force the soil to release the stored nutrients. I should have explained what cec was in case you don't know. Each type of soil has a different capacity. Peat will hold differently than Coir or compost.

I haven't used fertilizer in a while. What should I use? How much vinegar? Do I mix it with fertilizer? So tomorrow I should run a ton of water through it and then let it drain, then give it vinegar and fertilizer? It's best to do this in the morning so it dries out during the day or is evening fine?

I will also add that it does drain when I water it, but I don't know how much.

You have not told us in what zone/state you live in?

I also asked you what fertilizer you use? If your fertilizer contains Iron? Have you read the label and see what it provides?And, if you have checked the pH of your water, usually by calling the water provider...?

You already may have answered one of your questions by admitting you do not make it a habit to fertilize. How long is a while? Are we saying since last summer, or all winter? Do you water in sips, just enough so that the water does not come out or just barely comes out?

I am thinking your watering/fertilizing habits is not good and neither is the mix..But you can address the first two until you change the mix to one that allows you to water and fertilize more frequently without the fear of salt toxins and root rot which will prevent fertilizer uptake when you do..

A cap full of vinegar in a gallon of vinegar never hurt any my trees or that of the hundreds I know using it. Even if their water is fine..Most I know have too high of pH which make nutrients unavailable over time in their watering/fertilizer solution..

I think you may be making this harder for yourself than it is...As soon as you see fresh watering exiting the bottom of the pot, keep watering until the water has come by counting to ten....That will suffice. Morning or night, it does not matter if it is outside in lots of sunlight...Here it does rain at night and many times of which I get down pours...But for my trees, I like to water in the a.m because it's the only time I can do it..

Dynagrow 7-9-5. It says 0.1% iron. I live in zone 6 so they are inside under grow lights all winter. I water in winter about once per week just enough so a few drops of water comes out the bottom. In summer I water once every few days a ton so it drains out. I last fertilized probably in june.

Free draining doesn't mean it drains when you water. It means that it still holds significant air when watered. Which is hard to measure. Basically does the mix have pores for air or does the mix clump together?

I think we have established the fact that you are not using a free draining mix..Now you have to work with what you have until you begin to use one, which is very doable..

You can not water in sips and expect a healthy tree..The salts will build over over a short period of time AND your tree will look like that. That is why it's critical that you understand the mix you are working with and flush at least once a month until you do a re pot. That's my point. Your answers have determined in my mind that your watering practices in that mix and the way you use fertilizer is not correct.

Dynagrow is just fine although Foliage Pro is better..There is plenty or Iron in in to keep your tree healthy.

You should of fertilized your tree right up until at at least October in your Zone and you are still getting cold nights which also affects nutrition...When did you resume fertilizing and how do you use it? How much and how often?

I haven't fertilized since june. How often should I use it? Also even in winter I should be watering until it drains? So plan for now is water a lot to wash out salt, add some vinegar, fertilize, then repot with better draining stuff once growth begins in may or june?

Always water until it drains. Tap water still has salts in it and will cause build up.

So I should buy bottled water for this initial washing of the soil?

Pip,

Who knew you were a fellow creator??!! Some years ago in California I created Dox Blue (Dox, the Greek word for God; Blue for the color at harvest. It is now extinct; but the lineage is remarkably similar to what today is known as Blueberry. Maybe there is a crossover value of growers of citrus and "organic entertainment". Our best Meyer lemon growers are also growers of coffee; because the two require almost exactly the same care and chems.

No need to...Even bottled water has salts in it..You could use rain water or distilled water but faucet water would be just fine)

OK how often should I fertilize with the dynagrow and how much?

It all depends..There are many ways to use it..By directions, or by choice..

I use 1/4 strength per gallon at every waterings, then at times I use full strength per gallon once a week...Sometimes I go even heavier all summer at every watering. like a 1/2 strength...It varies.......It's a lot easier than you think to use..On this one you can always go heavier with no problems at all..With a fine mix such as yours only if you flush once a month or more often, with the mixes I use, I don't have to flush and never have an issue..