Info - Global Changelog | Page 20 | MineYourMind Community @SirWill posted that the Growth accelerator has been unbanned on 1.12 packs and has been given a block limit instead. However the block is still not craftable even after several server restarts. The recipe wont show an output.
I just tested this and while yes, the item doesn't seem to show up in the output slot, I found a very simple workaround for it. you can get the items needed to craft it, bring up the recipe for it in JEI and then click the "move items" button, it'll be the + box in the bottom right corner. This will allow the block to be crafted and obtained normally. I'm not sure what causes the output to not show normally, but this seems to work.
