Thanks for all the tips guys. I guess I didn't anticipate that it wouldn't work the way I thought. XD; I will say I did it wrong the first time, but I think I've gotten the hang of it now...as long as the stuff sticks.

Once I get this one wall done hopefully I'll have leanred from my mistake and use a lot more dirt. I don't think I piled it on enough the first time.

I have been doing small patches. Now there are just little pieces of the foam showing through, a bit below that ledge in the picture up there and some spots that are covered with dirt and silicone but you can still see the yellow a bit underneath.,

I've got this! It'll get done, just gotta give me some time to recuperate from my failures.

Hopefully I'll be posting pictures of the finished product soon.