Is 90% shade cloth ok?

i am not exactly an expert but i have grown a tree fern in NTH QLD by putting it under my stairs (very shaded area but alot of light) and pitting it in a shallow dish of water to keep it constantly moist. tho as soon as i moved it anywhere near the sun it burnt.. the cream shadecloth still might be letting a bit too much sunlight thru.. i hope i helped a little at least. good luck

Like Carmz and Marguerite I too have grown tree ferns before and during very very hot summers - maybe not in a 40 degreesC heatwave - and I used to have mine under shadecloth as well as out in the open. I used to put on the sprinkler right next to them on the hot days - in the morning and evening and that seemed to help. The tips of the fern would be black in the high temps but the fern kept surviving.