whats changed .... some history ...

repotted.. moved... etc ... ken

Well, I got them about a month ago from the nursery. So they have been in their current pots for about a month now. I have a regimen of watering once a week at this time of the year, and feed them Miracle gro bloom booster every other week. Also, my balcony does not get a whole lot of direct sunlight on its own, so I keep them under artificial lights for a few hours every day.

it could be a delayed reaction to transplant ...

how close to the lights are the plants??? ... they need to be 2 or 3 inches ... for most lights .... otherwise they arent getting much light ...

even in your zone.. its winter ... things slow down .... be patient ....

was there fert in the media you potted with .... i am not sure it needs as much fert as you are giving it ... though its not causing this .... imo ... if you insist on continuing on this schedule.. think about going at 50% of recommended rate ... btw.. when you water.. does it run out the bottom .. if not.. i would worry about accumulation of too much fert ....

ken

@rhizo_1 The Miracle Gro bloom booster I am using, has a 15-30-15 N-P-K ratio, so it's not really a hardcore "bloom booster" I think, but just has double the phosphates. I am using LED lights that emit red and blue wavelengths.

@ken_adrian The plants are about a foot away from the lights. I didn't think they need to be any closer than that, since these LED lights emit the optimal wavelengths, and being a foot away provides the greatest coverage. Growth has indeed been slow, but still visible, with new growth, buds and flowers, since I got them from the nursery. It's just that the new growth and foliage, are turning light green to yellow. The potting media did not have any ferts, and I was just following the directions on the label, which suggests applications every 7-14 days. But I can cut it down to 50% concentration. And yes, I do saturate the media every time I water, with water running out the bottom.

Let me rephrase.....it's a myth that plants need an abundance, imbalance of phosphorus in order to bloom. That's a 1:2:1 ratio.......3:1:2 is considered ideal.

So you think the yellowing of the leaves is most likely caused by an overabundance of phosphorus?

i fert my pots twice a season.. once a month after transplant shock.. and once in mid summer .. in my MI ... a 5 month growing season ... and when i do.. i do it at 50% the recommended rate ....

obviously.. your season is much longer ... but frankly.. i think you are over ferting ....

they are plants.. not children.. imo.. they dont need to be heavily fed ... they are supposed to be able to feed themselves ....

my light experience is with fluorescents .... i do not know if you are getting value at the distance you are using ... it would be better to have less coverage as you say .. and move them around.. than to have them too far away ...

i wonder if there is a light forum.. where you can get some info in this regard ...

ken

"So you think the yellowing of the leaves is most likely caused by an overabundance of phosphorus?"

nish, that's not what I said.....but it is very likely that the constant use of a high P fertilizer has caused an imbalance of available nutrients within the confines of the container. An inappropriate ratio with P as the most abundant element will lock up the N and other elements.....making them unavailable to the plant.

I mentioned the fish emulsion fertilizer previously because it will offer some essential micronutrients that your plants need, and at a more reasonable dosage of 4-1-1 or 5-1-1.

Contrary to what ken seems to think, containerized plants must be fertilized regularly. They need to have ready access to the essential elements required for normal, healthy growth and development.

Thanks to both of you for your suggestions! The thing that vexes me the most, is the fact that I have other plants too, including african daisies and a couple of other Supercal petchoas that have been on the same regimen, and acquired around the same time give or take a few weeks, that are not showing the same conditions and are in pretty good health. I guess this might just be a case of different plants reacting differently to the same environmental conditions. Anyway, I will try to get some fish emulsion and see whether that takes care of the problem.