touchy ficus help

So of my tropical bonsai I have a handful of different ficus, african strangler, burtt dayvi, benjamina, and one very touchy "green island".

I live in central Indiana and brought all my tropicals in a while ago before the cool weather moved in....they all get moved into a large bathroom on a shelf under T5 CFLs. I use both a blue/white grow, and red/orange bloom spectrum bulbs and no plant is more than 8 or so inches away from the bulbs. I have a hygrometer that i keep the humidity over 50% at a minimum. The bathroom receives adequate ventilation from two separate entrances and dont have any pest/disease problems other than the very occasional scale insect. Watering is on an as needed basis and am providing a low nitrogen organic fertilizer about once a month. I moved most of my tropicals into the shade for a couple weeks before bringing them in to acclimate them to the lower light as well.

Now, everything else is doing fine, only losing the occasional leaf and a couple are picking up some very slow growth. The green island ficus however was fine for a month or so and is now losing leaves every day. I know some leaf shed for ficus is normal but none of the others are doing it and im just not sure what is going on. The leaves go from green, to a pale green, then to an almost solid yellow, then fall off. Everything I read points to an overwatering problem but I would sooner believe the opposite, if the other ficus were also suffering. I have had one green island last year and it did the same thing until all the leaves were gone,and most of the branches died back. That one never recovered. I have a decent hydroponic/horticuture hobby background and this is driving me crazy. Any help or advice is greatly appreciated.
Cheers
Blake

is it the inner/old leaves or the new ones as well? I wouldnt fertilize in the winter. check for spider mites under the leaves. Keep the soil slightly on the dry side.

yellow leaves on ficus can also be indicative of under watering as well. Its a water stress thing with that one almost certainly, also you don't need the red/orange bulb in there better to just have two blue spectrums. I'm not an expert with green Island although I have many Ficus I don't have that one. Billy's the ficus guy he'll know.
-Jay

Hey gentlemen, thanks for the replies so far.

the yellowing does not seem to discriminate between inner leaves and ones towards the end of the branch. So far most of the inner ones are gone but the outer ones are following them. I will def try to keep it on the dry side as much as possible.

No signs of spider mites whatsoever. As far as the bloom spectrum bulbs, they are mainly in there for the buttonwoods and portulacaria that I have in there as well as they seem to fair much better through the winder since I began using them. Each of 3 shelves has 3 blue and 2 red over them.

Thanks again

Blake

drgonzo wrote: Billy's the ficus guy he'll know.
-Jay

I am honored that you think of me as the "Ficus Guy." While I do have a lot of Ficus, I am not an expert.

My Green Island sometimes drop more leaves than they should but it is usually from being too wet.

Mojojava, can you tell me what soil you are using and when you last repotted the tree in question? Is the pot glazed or unglazed?

Again thanks again for the replies.


Yeah i get a small drop from all my ficus when I bring them in but it is minimal and they quickly acclimate. The green island just seems to continue to go yellow well past all the rest.

AS far as the soil I use wigerts mix of pine bark turface and lava. This what I use for all my tropicals. The green island was repotted last spring and is in a plastic training pot with plenty of drainage and room to grow. My camera is currently being borrowed or i would gladly take some pictures and will do so as soon as possible.

BLake

room to grow.

This might be your problem. Too much empty soil in a pot stays wet because the tree has no roots in that area to use up the moisture. The rule of thumb is, no more than 1/2 inch of empty soil around a root ball.

Are you sifting the soil before use. The pine bark especially can contribute a lot of "fines" and keep a soil extra wet. Next time you repot this tree try using only Turface or a commercial potting mix with coir, which is what I use on this species.

Please keep us posted regarding your ficus. I'm experiencing similar issues with a tiger bark ficus. Older leaves lose their coloring, becoming "splotchy", then turn yellow and fall off. It is producing new leaves but not quite keeping up with the leaf loss. Also, I've noticed that on some of the newer shoots, when the sheaths open up the incipient leaf is dried and black, which I think probably indicates insufficient water. Not sure, though. At one point I thought I might be over-watering, so I cut way back and may have gone too dry for a while.

Mine was acquired and repotted late in the summer. It was in a tiny pot so it went into a larger (but I don't think excessively so) pot with high quality bonsai soil. It is indoors under fluorescents, along with other tropicals that are doing well.

Chris

When plants are under lights, indoors they don't need much water because they don't grow or transpire. A plant with any more than 1/2 inch of new soil is going to stay too wet unless you are very careful. I suspect since the plant was repotted late in the season and UP NORTH as we say here, it has not grown new roots into the new soil. A good way to check is to pick up gently on the trunk, if the plant has not grown it will pick up easily. You might need to down size the pot.

Thanks for your thoughts, Billy.

In my case, the plant has grown at least some new roots (evidenced at the drain holes and also some that pop up along the soil surface), though not enough to fill the pot I'm sure. The shape of the root system dictated a certain size/shape pot. I'm using the chopstick/toothpick method to evaluate soil moisture and it seems reasonable. So for now I'm going to stay the course and try to keep control of the watering - it's a learning process because I haven't grown ficus before. If the plant shows further stress/accelerating leaf loss I'll unpot it and evaluate.

Chris

Are you fertilizing it Chris? The dried and black new leaf made me think you caught a fertilizer burn.
-Jay

All the tropicals get a dose of weak fertilizer every 2 weeks if they're growing...which all are (including another ficus). But at some point it could have gotten too much. I think it's more likely that I haven't quite figured out how to water this specific plant yet as everything else is doing well.