Answer:
You eat something you neither plant nor plow. It is the son of water, but if water touches it, it dies.
Something wholly unreal, yet seems real to I. Think my friend, tell me where does it lie?
As soft as silk, as white as milk, as bitter as gall, a thick green wall, and a green coat covers me all.
What has a spot and is very bright, is sometimes, red, white, blue, yellow or green and is often blinding.
I have four wings but cannot fly. I never laugh and never cry. On the same spot always found, toiling away with little sound.
I am owned by Old McDonald.