My tree farm is not growing even with bonemeal

Question

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.

Answer 1

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:

• Small oak trees need no ground level clearance, 1 block clearance at the trunk, 2 blocks from the top of the trunk to the ceiling, and 6-8 blocks of vertical clearance. Thus you could put the sapling in a one-deep hole but not a two-deep hole.
• Large oak trees need 4-14 blocks of open space above the sapling, but otherwise can be completely enclosed on all sides.

Spruce:

• 1x1 spruce trees need a minimum of 5x5x8 blocks, and need an empty space above the topmost leaves.
• 2x2 spruce trees are grown using 4 saplings. They need a 6x6 space starting one block above the saplings (4x4 at sapling level) and at least 16 blocks of vertical space.

Birch:

• Birch trees also don't need ground level clearance, but starting one block above the sapling, they need a 5x5 space between 6 and 8 blocks high. Birch trees need the 5x5 level above the top of the leaves to be completely air, not even torches are allowed.

Jungle trees:

• 1x1 jungle trees need there to be no blocks adjacent to the sapling up to the height of the tree.
• 2x2 jungle trees need to be planted using 4 jungle saplings. The northwestern sapling must have no blocks adjacent to it up to the final height of the tree, as it is considered the "center" of the tree. Furthermore, there can be no blocks one block away except at the same level as the sapling. In other words the tree needs a 5x5 space from one block above the sapling to the height of the tree. These trees can be anywhere from 9 blocks to 44 blocks tall. Bonemeal can be used on any sapling.

Acacia trees:

• Specific space requirements are not given on the Minecraft wiki, but Acacia trees are typically about 8 blocks high, so likely would require at least that much space to grow.

Dark Oak trees:

• Dark Oak trees must be grown from 4 saplings in a 2x2 grid. They will not grow from a single sapling. They need no clearance at the sapling level, but at least 4x4 above that.

Answer 2

You need to add space around the trees for them to grow.

I see you are using oak saplings so you are trying to grow an oak tree.

There are several types of oak trees, including small oaks, large oaks, balloon oaks and swamp oaks. I will be finding the space needed for a small oak as they use the least space.

After trying to grow the sapling in multiple conditions I have found that the smallest space for an oak tree to spawn is:

5 blocks wide x 5 blocks long x 6 blocks high

Note: The actual tree only took up 5 x 5 x 5 blocks of space, but wouldn't grow without the extra block of air above it.

There are several types of trees in Minecraft and every tree has different growing conditions. I recommend looking at this page on the wiki for information on the love and care needed for each tree.