I've been trying to get GSP to cover my back glass. Super glued probably 8 patches to it at various times. All but 1 fell off after 4-5 days. Sticks for awhile, sure it's going to hold, then it falls off. lol But the one patch that's stuck for real has been on there about 10 months. It's growing...but mostly downward onto the sand. And as was said, then it just plates out and grows on top of itself.
If anyone has any tips for getting GSP to stick to glass, I'm all ears. I've got it growing on rocks and then laid against the glass..... it still doesn't want to creep up it NEARLY as fast as it does everywhere else.