I would think a Chinese quart take-away soup lid with the lip cut off would be an adequate substitute.

Cheers.
Jim

wouldn't this restrict air flow?

The plastic lids would work but you might have a problem getting them over the plant if they are very rigid....Perhaps a cd cut in half with a bigger hole in the center could be used ?
You could then slide the two halves togather from each side and have easy access to remove one half or both if needed for any reason.And they would have the silver color also just like mylar ..in fact that is actually the same aluminum used for mylar I think.

That's a great idea! I'm always finding miscellaneous scratched, unlabeled CDs near the computer... that would be recycling too. :D

I don't know that the aluminized aspect is really necessary.

I think you'd do just as well by cutting a circular section out of a plastic storage bag, the cut a hole in the center and slit from the edge.

And you'd do even better for the plant if you just figured out how to increase the ambient humidity!

So the idea is just to hold humidity in the LECA stones?
I have 2 ultrasonic type humidifiers going and I can barely keep the humidty above 30% during the winter. Now that it's getting spring-like it's easier. Challenging, growing these plants- too bad I'm completely hooked!:blushing:

That's right, although I suppose to be more precise, the idea is to slow the evaporation rate.

air... flow...??

After reading this thread, I tried to use coconut material (the kind you put in hanging wire baskets to hold in the soil) on top of my phals in their new S/H pots. I am thinking this was a huge mistake because the roots at the top of one of the pots rotted in less than a week. Of course, I live in Louisiana and my humidity varies between 60% and 70%. So, I think if you have high humidity, it's best to just leave the top of the pot open and let it breathe. The root rot freaks me out, but I have to just keep reminding myself that it's part of the process. :(