[David]

Yes, I woudl think if you are growing them outdoors with sand as the topping, it'll barbeque the plants. Sand can be quite hot under sunlight.

This pot is place at my wash area at the window. 6 months in a year it receives direct evening sunlight for about 2-3 hours. It's ok like that so far. But if it's place under direct afternoon sun the whole day, your plants will get barbeque like what Ban Aik said.