Why are my trees in Minecraft not growing?

I'm trying to grow trees underground, and they are not growing?? I have other underground spawning locations, and they grow fine. The depth here is 17. Could that matter? Ceiling is 8 blocks up. Very confused.

Note: narrowness of the area is not the problem, see photo below.

Solution 1:

I'm not sure why you decided to use a hoe and pour water. Trees don't need those conditions and... actually don't grow on farmland! Only plain dirt works.

[Prior to 1.7.2 the above behavior was considered a bug. As of 1.7.2, this behavior has been fixed. The bug database entry for this bug is here. The above behaviour was causing the problem. The discussion below causes (on average) more than one bonemeal to be consumed when growing oaks in this configuration.]

One more problem could be that there's not enough space. Other kinds of trees require a 5x5 space.
I just tried to grow an oak close to a wall. It succeeded, but required about 10 bonemeals, and that's probably not good.

One more thing. I would remove those torches on the walls. As they are "transparent" trees will replace them anyway. Torches near saplings should be enough.

Solution 2:

Trees grow in much the same way that mushrooms do, namely, they don't grow up the trunk and then sprout leaves; as far the game is concerned the branches sprout pre-made. What this means is that you need a bigger area for them to grow...at least two more blocks over the 4x4 area you've given them. to quote the wiki:

All trees in a large radius around the player make attempts to grow at random intervals. For any given tree this can work out to about 3 attempts per minute, but a tree will usually not grow until nearly 30 minutes have elapsed since planting. When the tree attempts to grow it first checks that it has enough light, then chooses either to spawn as a Large Tree or a Small Tree. Large Trees require 4-14 blocks of open space directly above the sapling to grow (Air or Leaves only) but can otherwise be completely enclosed on all sides (which allows for the phenomenon of 'Tree Tubes'). Small Trees require no horizontal clearance at the base, 1 block around the main trunk, 2 blocks from the top of the trunk up to the ceiling and 6-8 blocks of vertical clearance (Thus a Small Tree can grow in a 1 deep hole, but not a 2 deep hole). Now that the tree has passed a light check and chosen a type of being either Large or Small, it checks if there is space to grow into what it has already (randomly) chosen to become. If it encounters an obstruction during this check, it fails to grow and must wait for the next pass before it can attempt to grow again. This means that a tree in an open field with enough light will grow quite quickly (usually right around the 30 minute mark), but a tree in a tree farm that stunts its size may make several attempts before finally growing. Bone Meal forces for the tree to grow if right clicked as long as all of the normal checks are in place (i.e. light, space, dirt, etc.)

(http://www.minecraftwiki.net/wiki/Trees)

Solution 3:

I suggest spreading the area out that you are planting the trees in.