I have this hobbit like green house that's 7x7. The roof is laid out like below (where g is glass, and w is wood with a little dirt on top.) nothing is blocking the glass and its above 50% of the roof.
g g g g g g g
g g g w g g g
w w w w w w w
w w w w w w w
w w w w w w w
g g g w g g g
g g g g g g g
Now the weird part is that, the game registers some of it as a greenhouse. Is there like a period where it slowly effects every block after building? or should all the blocks update at once?