If roots are protruding from the bottom of the rock wool, the seeds are off to a good start, and it's time to go to the next stage of planting.
(roots; are protruding; from the bottom of the rock wool) (the seeds; are; off) (it; 's; time to go to the next stage of planting)
roots the seeds it
are protruding are 's
from the bottom of the rock wool
off
time to go to the next stage of planting