I'm trying to grow 2x2 spruce trees on FTB infinity evolved skyblock, but they won't grow. I tried adding another layer of dirt below, a layer around, putting a torch and also used a lot of bone meal.
Can anyone suggest what could be wrong?
Here are some remarks about growing trees from the Minecraft Wiki:
In order to grow a 2×2 tree (be it spruce, jungle or dark oak), four saplings must be placed adjacent to each other in a square. For growth to succeed, there may be no blocks adjacent (even diagonally) to the north-western sapling (which is considered the center of the tree) up to the final height of the tree. Which sapling the Bone Meal is used on is irrelevant.
2×2 spruce trees require a 5×5 column of unobstructed space at least 14 blocks above the saplings to grow (15 blocks including the saplings themselves). This column is centered on the northwestern sapling. A 3×3 area is required at the base of the tree (the level of the saplings).
Therefore, you should check the space above, because there is a lot of space needed. You should meet the 3x3 base area requirement, but just to be sure you could add another ring of dirt at the base.