Mandarin Leaf Curling Down

Gradmaster Yoda starts with ...
Hey I've noticed my mandarin tree has leaves curling downwards and over time it's "spreading" and happening to more of the leaves. I'm assuming it's just the cold wet weather and that the soil hasn't had a chance to dry out much. Just thought I'd post to see if anyone thinks it could be something more serious or if I can just wait it out. Cheers.

Pictures - Click to enlarge
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Amanda says...
Are these both Imperial mandarins by any chance Julie and G/Yoda, out of interest?

Julie says...
Mine is, Amanda. Must try and remember to take a pic tomorrow.

Gradmaster Yoda says...
No Amanda I don't believe it contains all the necessary trace elements it's just a basic fertilizer. I haven't had the tree for very long. Also its potted if that helps.

Could you recommend a fertilizer? I would appreciate it.

Gradmaster Yoda says...
Okay thanks Amanda I looked up the product analysis for my fertilizer and it looks like it does contain all the necessary elements. My tree seems pretty happy otherwise with new growth, blossoms and growing fruit so I'm not too concerned.

Julie says...
I'm an organic grower, so as I said above, I feed with Seasol and Powerfeed roughly every two weeks, when I feed my other plants.

They have certainly responded to this, with nice green leaves and quite a lot of fruit for such a small tree.

Gradmaster Yoda says...
Thanks for that Amanda. That's unfortunate that Bunnings hasn't updated the error.

The product analysis I refer to is directly from the manufacturer so it should be accurate. I would also recommend to anyone that it what's in a product is important then you should try and get information from the manufacturer.

jakfruit etiquette says...
The richgro is a 7-1-7-9 fertilizer on the label, thats NPK plus something, probably S from the other bits of the NPK, ie ammonium sulphate and potassium sulphate I would guess.
Thats the added trace on the website, as you say, not a complete trace spectrum, and not what you are expecting. Strictly not a trace, but a main minor fertilizer element.
You have to read labels carefully to make sure each of the trace are there, and also how the fertilizer is constructed. Iron sulphate, magnesium sulpate, zinc sulphate plus other sulphates will give a high S value.
Many fertilizers will have no Calcium at all, some will have NPK S Mg Zn Fe but not the rest.

Amanda says...
yup, it's sulphur j/ettiquette :) But here in WA that product is 9-1-7-12 (pics from a bags I have here)

The NPK ratio's can vary a little over here, for the same products, because by our WA Environmental Protection Reg's (2010) our 'packaged' fert's must have a minimum N to P ratio.
This is because of our sands and their leaching/water pollution issues - also P fixation problems.

So our Dynamic Lifter, for eg, is made and bagged here in WA - and it's not the same product or ratio's as the Eastern states (and it's double the price here now..as it's made by Yates instead- not DL...grr...and hence why I have changed over to a local product instead - Multigrow Organic 2000 - for a good price/kilo)

The sulphur ratio's might also be a little higher also though?
Certainly many of us on the near/close-coastal sands have issues with akalinity as well, especially as our bore water may be becoming more alkaline over the years - and also saline in many areas now.
So sulphur is usually needed in higher quantities as well.

I avoid any fert's with a calcium % above 5% ...and especially those where the calcium is in the form of lime (carbonate form) ...because I get enough of that from our bore water - and I need to avoid more carbonates like the plague. Nasty stuff for plants.

I don't want to add even more levels of calcium because as much as it is needed in decent amounts - you can have too much of a good thing too, can't you.
3% in a fert works ok for me here, in my situation - but as calcium in the sulphate form (ie: gypsum)
Potassium in the sulphate form - not muriate...etc etc.

We only need to look at the exchange affinity/lyotropic series to see that calcium-in-excess could knock off the lesser cations, that are needed, on the soil - like Mg, Zn and Mn..if they are in short supply.

I have enough calcium in my system from both the irrigation water and the type of sand we are on here (Spearwood sands) - so don't need much in my fert's - just need to keep it all balanced.

This is my understanding of it all now - after a good 10+ years of homework and experimenting etc...and a lot of errors and deaths in the 'family' too...lol...
Any advice and/or experience I pass on is only for sandy soils +/- alkalinity though...and/or perhaps with the climates I have actually grown/gardened in.
I have limited clay experience, for eg, and even less with acidic soils - so I usually avoid remarking on those situations.

You are absolutely right tho - if the bag doesn't mention cobalt, for eg, then there will be no cobalt added...especially given the price of cobalt..!?

I think sometimes that it suits the fertiliser companies to simply omit what is *not included* .. ? ;-)

I have really changed the way I think and use fert's over the years tho....
I used to be totally organic-derived slow release....but I just found it so hard to find a slow release organic source of higher nitrogen levels - for the heavy feeders, in our sands.

One I have found and down here has been pure dried blood meal (No hoof, horn or bone - which add more calcium)

It's a bugger to use tho....so fine and fly-away and stinky...plus seems to aggravate water repellency.
I want to try feather meal next.

Pictures - Click to enlarge
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Gradmaster Yoda says...
I had a look at the pictures on that thread and I'm guessing it's a different problem. Unless of course my problem gets worse (which it hasn't yet and seems to have stopped) my leaves are curling not much past 90 degrees down.

Recently treated my tree (a couple of days ago) for citrus leaf miner (also took care of aphids it seems). Could the pests have caused leaf curl like this? The miners weren't attacking the leaves that are curling down just the flush.

jakfruit etiquette says...
The theory of specially formulated to promote high quality and yield, that would mean a N level to promote growth and flower/fruit set, without an excess high N to give excessive leafy growth or N burn problems.
The K level of 7 would help with fruit quality, disease resistance.
Possibly the Sulphur would help there also. The P of 1% is there to give supply without excessive response. I'm not reccomending this fertilizer, just interpreting what it says. If you doubled the NPK to 18 2 14, you would get an explosion of green growth, and probably fungus disease and insect problems on foliage and fruit.
Fertilizers dont only feed the plants they are applied to, they also stimulate the soil microbes, and breakdown organic matter in the soil. This can liberate other trace elements.
Weeds can also pull nutrients into this process. I wonder how they change the formula in WA from 9179 to 91712 without altering the 917 ? Maybe just add plain S ?

Julie says...
Just scheme water amanda, no bore. And yes, it's the same mandarin, the one in 'Trees in Bags" from many years ago.

G/master Yoda, in general I fertilise trees in ground twice a year, and trees in pots/bags little and often.

Amanda says...
Julie - I am amazed the bonsia bag has lasted 20yrs!? Can you post a pic of it please? That's remarkable durability, especially these days...
And it's even more interesting that you have never re-bagged it...I wonder what the root system looks like in there..
It's nice to see you are still here on Daleys btw :) ...and still spreading your rough Seville seeds far and wide..