I am playing on vanilla 1.7.2, and I trying to get trees to grow underground. I gave 60 bonemeal to a tree, and it would not grow… How many blocks high does my room need to be? Here is a picture.
I realized I actually that picture is not updated, I raised the ceiling by one block.
I googled on tree growth behavior and they said room has to be 4-5 blocks high, but the trees still won't grow.
Best Answer
Most trees in Minecraft will not grow when there is a block next to them. This can be something as small as a torch. You'll need to make your room larger. You will also have much better luck if you make the room at least 5-6 blocks high - you'll use much less bonemeal on them (or they will grow much more quickly if you are letting them grow naturally).
Specific requirements for tree growth:
Oak:
Spruce:
Birch:
Jungle trees:
Acacia trees:
Dark Oak trees: