Before you say "Just give it some fertilizer", please look at my post about that plant before.
It started flowering a few weeks ago, and the roots are growing back very healthy, but slowly.
I think those two factors are what contributed to the plant consuming itself, as you can see on the pictures where the lower leafes start yellowing quite significantly.
If they continue to do so, I will loose them, and that would suck.
My question is: What can I do to mitigate that, so I can prevent the leafes from dying off completely?
I already cut off the flower spike to redirect the resources, but I fear this isn't enough.
There's a shit load of fertilizer in the substrate now too.
I grow it hydroponically, and started with an EC of just 1 mS, because that's what's recommended for orchids, but I quickly realised that this isn't enough, and increased it to 1,5-2 mS. Right now it sits at about 2-2,5 mS, which is objectively on the higher side for other plants, but very high for orchids from what I know.
But on the other hand... it needs to grow a lot of plant matter.
The problem is, that there are probably not enough roots to support this growth, and the nutrient uptake is limited because of that.
Still, I don't want to loose the leafs. Would foliar fertilizing help? Or is it too late?
Here are root pictures my other two orchids that I rescued too at the same time. They don't show signs of a deficiency, but also regenerated a lot of roots. Maybe this helps?
Are the clay pebbles new for this plant? I often understood that the older roots from before semi hydroponic will die in those conditions and new roots will grow and be adapted to those same conditions. I used a similar setup with no fertilizer at all and got orchids to flower for a few years, the growth was just a bit smaller every years. They need way less fertilizer than you think : because they grow as epiphytes in the wild without access to soil. Intermittent very low level of fertilizer might be better especially if the leaves are showing sign of a mismatch between root surface and leaves exposed surface (to drying that can be helped with higher air humidity)
Yes, the expanded clay substrate is new.
They've been in an organic medium (bark and coco I believe) at time of buying, but looked pretty much dead when I got them, as you can see in my previous post I linked at the beginning. Most of the roots were mush back then, but they started regrowing very healthy now.
The higher levels of fertilizer didn't seem to be harmful as of now, since it's still in the non-toxic zone.
My plan has been to keep it higher for now, to compensate the lack of roots, and to reduce it further more to a normal level as soon as they've regrown fully.
So, you would say I should reduce it now to a very low level?
Is foliar feeding better? I don't want to loose the already yellowing leaf, that would suck.
My philosophy is to only consider fertilizer when there is active growth and it comes second to water balance: root surface vs foliage surface vs temperature-light x deficit in air humidity. Like Russian dolls i don’t look into the next lower priority step if i am not satisfied with a high priority step : medium-high indirect light and water balance. N.B. Light is also a factor in water balance: the plant open stomata on the leaves to absorb CO2 under high light and doing so can dehydrate a bit more. Keep your conditions stables and the plant will adapt, wont be the most beautiful orchid but it should adapt if the roots aren’t rotting too much. I successfully kept cattleya, oncidium and phalenopsis in such conditions of years before i moved to terrariums.
I am surprised that the leaf showing a touch of yellow isn’t the bottom one.