I would suggest spray-feeding them. All your media ingredients are basically inert and devoid of any kind of food whatsoever. P. moranensis is a fairly large Ping--I would not call it a "heavy feeder," but keep in mind it usually supports a lot more foliage than a lot of other species. Chlorosis, if you can establish that it isn't high light or overwatering/rot/root loss, can often be traced back to nutrition. Particularly if you have a plant that has remained the exact same size for quite awhile but otherwise seems healthy, it's usually one of the signs to look for to establish whether or not a plant needs feeding.
If you feed them and they green up, then your problem's solved. Conversely, if you feed them and they don't green up or grow, then it's most likely that your temperatures/lighting are too high.
As for a rate, I'd say 1/4 tsp per gallon of something like Peter's 20-10-20 once weekly should do the trick. You can go up to 1/2 tsp if you notice it working really well. Also, could you post a pic of the others so we can see how green they look?
Last edited by theplantman; 01-11-2014 at 10:02 PM.
Hey theplantman, thanks for the advice. I was a bit scared putting fertilizer on the plantlets due to their size. I had a couple die on me near the very beginning of my cultivation endeavors using maxsea. In hindsight I think I just over sprayed them at the time.
I had purchased some freeze dried blood worms shortly after I posted this, ground them into a quasi - powder, and sprinkled them on most plants. I also sprayed some of the other plants with maxsea so there was bound to be some over spray that reached the pings. It has been about 2 weeks now and there is significant greening and growth. I took some more pictures of everything I can post a bit later (posting from my phone) and you can see the difference. The ones in the square pot are actually visible in the photos as opposed to being washed out by the light of the nearby terrarium.
I think I have decided to start using a small amount of peat in my mixes. I noticed in my cyclocecta pot that the peat has established a decent springtail population. Once the plants reach a larger size they seem to easily get caught. Nothing beats a pot that holds the plant and feeds it!