I don't know if I can advise you about feeding as far as what to use, because we grow under very different conditions. Almost without exception, my entire collection of aroids, including all my anthuria, are grown in the ground. I have a few flamingo flowers (A. andreanums) in containers on my front porch, and a few huge birdsnest anthuria (with spreads of 4-5 feet) in big 35 gallon containers just for mobility's sake, and I have a few, like A. reflexinerium and A. jenmanii in treefern bowls just because I haven't decided where to plant them yet. When I do the whole thing will go into the ground. But, even then, I use the same fertilizer on them that I do on the ones in the ground at the same strength. I use a hose end feeder and spray them with 15-30-15 or 20-20-20. I also give them a spritz of micros every 4 months when I give my palms a chelated iron nutritional (actually I give this to each and every plant in my greenhouse every 4 months...orchids, aroids, trees, heliconias, gingers, etc etc...) I don't believe that 50% shade cloth is necessary for anthuria. If I were you I would try brighter light and food. I don;t know what kind of greenhouse you have, but, if its at all possible, I would try some form of giving the plants more of the feeling that they were in-ground. Planting in ground would be best, but if you can't, maybe big wide more shallow dish gardens instead of deep pots. Or if you could, perhaps the hollow treefern bowls that I use might help. They like to send roots out shallowly under the soil, not necessarily down deep into the soil. I think the "epiphytic nature" of them is more satisfied that way with better aerated soil. The other thing to do is to look at your collection of anthuria and research up on each one. All anthuria are not created equal. Some come from much higher altitudes than you and I are at, and don't really appreciate heat and humidity...they want cool and humidity, like cloud forest conditions. I try to stay away from most of these. These are the ones that I would tend to try to put into more shade. Others are happy in hot humid or warm intermediate humid environments. Make sure also that you are giving your plants a day/night difference in temps. A 15-20 degree difference between day and night temperature is what most plants like, not a continuous 24 hour stable temp.

Thanks Steve for all that information

Sorry, I got tongue tangled on this post. The IAS show is in the fall, this one could possibly be in the spring.

Just a follow-up if I may. About one year ago there was some discussion regarding the way Dr. Darian grows his Anthurium regale seeds. One seller made it appear in their ads Mardy was growing them in water. I questioned that approach. I was "scolded" for even questioning how Mardy grew his plants since I suggested at that time growing Anthurium species in water was not wise as a result of conversations with top aroid botanist Dr. Tom Croat. I then called Dr. Darian and we have since had at least four conversations regarding his technique. Mardy has initiated at least two of those conversations. Dr. Darian does not actually grow his juvenile Anthurium regale "in water". He places the seeds and starts in sphagnum moss in what is effectively a pot. Those are then placed in a shallow pan of water (about 1 inch) and the moss used as a wick. The effect is the moss draws water up to the plant/seed. The plant is not growing sitting in water. Dr. Darian has had great success growing with this technique. But if you speak with him directly you'll learn he is attempting to create a micro-climate that replicates a tropical environment in the dry southern California region where he lives. In fact, he has been very successful creating such micro-climates all over his property. We have also had great success growing Anthurium species including an Anthurium regale which has repeatedly produced very large leaves and is currently in the process of producing a second spathe and spadix. Our collection contains over 70 Anthurium species, many rare and some quite large. If you'd like to read our personal research on this species which was done with the help and guidance of Dr. Tom Croat of the Missouri Botanical Garden, LariAnn Garner of Aroidea Research and Julius Boos who is one of the country's most knowledgeable aroid experts, you can read about what we've learned together at this link. LariAnn was of great help to us and recently posted on this board in a separate link a note saying she had changed her own technique in growing Anthurium regale plants which came from Dr. Darian as a result of what we all learned together. If you contact LariAnn I'm certain she will tell you she does not grow them in water. There are several pages which track the entire progress of Anthurium regale producing a spathe and spadix. If you're serious about growing Anthurium species, you may find these pages useful. Here is a link that might be useful: Growing Anthurium regale