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[Saros]

I have mine (4 plants largish plants) indoors for the winter and they're starting to yellow after about 3 months being indoors. My house doesn't get much natural light at all so I'm forced to rely on artificial light to get them through till spring.

I did the usual PH & NPK tests for good measure.
   PH was high ~7.0 (I'm working on bringing that down)
   N is sufficient
   P seemed lacking, though after letting the test sit longer, it looked OK. So I'm not too sure about this but I don't think the leaves have a purple hue to the them or the veins. I'll have to take a better look under good light.
   K is sufficient

My first thought was it was a light issue but even the leaves that are inches away from the lights are pale and the rest of my jungle seems fairly happy. I have about 600W of LED lights above a 3x10' area. I think it's a little skimpy on light, but I'm just aiming to sustain the plants until I can move em back out to the greenhouse in a couple months.

So the first thing I'm targeting is the PH. What do you guys think? I understand they prefer acidic conditions. Anyone have any recommendations about lowering PH organically? Currently I'm just using diluted leftover coffee to water and adding coffee grounds to the soil.

[Mandrake]

My couple cents according to my little experience...

Maybe pH wouldn't be my first suspect, and even if it was, changing it significantly (and staying within organic) would take pretty long, winter would be most likely over by then - so I'd try other measures in the meantime, if the yellowing becomes a concern.

Unless the yellowing happened suddenly, light could be a cause even if you have a decent potency in the case of LEDs. 600W sounds like a lot, but you know LED technology in gardening can be more or less efficient depending on the individual wattage of the LEDs, besides the overall wattage output. Also, there's the spectrum. Some plants seem to really miss certain ranges. Are you positive your LEDs provide enough? Not that you'd need to get any extra LEDs, if that was the reason... I have a young caapi going nicely through the winter under a fluorescent fixture.

I suppose there hasn't been a big temperature change for them being indoors, and that there was no excess washing of nutrients.

If the problem is in nutrients (or pH) I'd try foliar feeding. Foliar iron, copper, zinc and such should then allow for some recovery as the soil is fixed.

Mandrake

1 Like Sunshine likes this.

[Saros]

Thanks Mandrake!

Temperature, humidity, and watering has been fairly constant for them so I'm pretty certain I can rule those out.

It could be a spectrum thing. Two of the LED fixtures output in 9 bands, but surely there are some gaps when compared to natural light. Maybe it's missing some key wavelength. Total output in terms of Lux seems sufficient.. especially in the upper portion of the vine where there isn't so much distance between the lights and foliage.

I'll try experimenting with light and foliar feeding. Since I have 4 plants doing the same thing, I can play around with different things on each plant and hopefully pinpoint the problem.

1 Like happyconcacti likes this.