I personally would ask, why 50% shade cloth? I think your plants might need more light. Are you feeding them regularly? I feed mine pretty much weekly during the growing period between March 15 and December 15.

Thankyou for your reply.
Most of my Anthuriums come from Ecuagenera, Ecuador and have been advised by them to use 50% shade cloth even though here in UK the sun is nothing like as strong as in Ecuador.

As for feeding, no i havent been feeding and maybe that is the answer, which feed do you recommend regarding strength, is a regular houseplant feed such as baby-bio too strong having 10% nitrogen or would it be OK.

Chris e

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.

Thank you for taking the time to answer my question so thoroughly, your help has been very much appreciated.

chris

Here are a few pics I took of a few of mine today.
The first photo is unfortunately a bit blurred, my 50 year old eyes are not what they used to be LOL
This is a small Anthurium faustinomirandae (largest leaf is about 1.5 ft x 2 ft)
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Anthurium regale
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Anthurium reflexinervium in the hollow treefern bowl, I grew this from a seedling that was only about 2" x 3". It has a spread of about 15" now
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Anthurium plowmanii
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Anthurium willifordii, also in a treefern bowl sitting on top of a pot of soil (this is an old plant, I guess about 10 years old, I grew it from a small seedling as well)
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Plants look lovely and healthy and it looks like you have a nice sized greenhouse too.
I have repotted some of my Anthuriums into more free-draining compost, something similar to an orchid mix and the growth started again on most of them but the Anth.Regale has yet to start but i have always thought it was a slow grower.

chris