i had to split the answer cuz it was too long... :(
then i paused the save, selected the water element and drew it on top of the seeds, when i unpaused i kept holding the draw key to support the sand platform and waited till the trees started growing, them let go of the draw key and the dand fell away.
the answer: a very fast and percise movement of element selection and cursor, FIrst; I put some seeds in the save, as the were falling i selected the sand element and started drawing with thee sand constantly, creating a temporary manual platform without any solids,
beep beep! oh, that's my lie detector going off!
If you didn't grow them on a platform and delete it, how did you grow this?
no i diddnt plant the seeds on a stationary platform, grew them, and deleted it.