Forge version: 36.0.7
Futurepack version: 21.0.7

I can't get saplings to grow on the Grass Sapling Holder. Neither Bone Meal or raising randomTickSpeed helps.

Using Bone Meal can put the sapling into stage:1, but it will not grow it into a tree.

On the other hand, Menelaus Saplings do grow into trees on Sand Sapling Holders.

turn out you need to add the sapling holder to the minecraft:dirt tag

edit forge:dirt