Can trees grow without sunlight?

7 blocks of height is required.

A neat trick is to put stone next to the saplings, so you don't have tons of leaves that you have to deal with.

from above, this is what I do:

XXXXXXXX
SXSXSXSX

XSXSXSXS
XXXXXXXX

S <- Sapling X <- Rock

Note, the Sapling has to be planted in dirt. Put torches on the rock pillars to light the saplings,and you are good to go!

Any light will work for trees. However, you may need more space.

My underground (automatic >:D) tree farm is 200x200, for the trees at least, and I've found trees require at least 1 block on all sides, and at least 7 blocks up. I have it at 10 right now, but to get the bigger trees you'll have to expand it to around 20-30. To get large jungle trees, you need around 60 blocks space, and yes, I have done this before.

I have heard hat you need at least seven blocks of space above the trees. As the last person said, bigger trees require more space. So yes, trees can grow underground. BUT MAKE SURE YOU HAVE TORCHES!

I know this is somewhat old thread, but here goes...

Bring bone soup (just mash bones of skeletons) and throw it at the tree and it works as a super fertilizer. If it doesn't grow, your tree does not have enough space. Sometimes you need to use the fertilizer several times for the tree to grow. I wouldn't waste more than 5-6 to see if the tree "pops up".

Just my 2 cents.

I know this is an old question but I had a few things that might help.

There are four things you must have to "grow" the tree: 1xdirt block, 1xsapling, 4xtorches, space.

The space is tricky. From what I have read it is probabilistic. When the sapling "grows" a randomly created, fully formed tree tries to pop into existence. If there is insufficient room for the new fully formed tree it will remain a sapling

I was successful with a birch tree, 8 torches on the walls, 8 high, 5 empty blocks in each direction