At first the farm was made of oak wood, and was not producing enough wood, so I moved it out of the ground, to above ground level (I live in a mountain) and made the design again. On the 11x11 platform, the jungle trees will not grow. I have put in countless stacks of bonemeal and fertilizer into the saplings and it will not work. However, about 3 blocks away from the 11x11 where it is normal ground, I can grow a jungle tree with absolutly no problem whatsoever.
I would like to know why it is not growing on my platform, but is working just blocks away.
I put pictures of the underneath below the square, even though that shouldn't even matter.
link to the youtube video that I followed: