Can't get birch trees to grow in skyblock, I have them at lvl. 1. They were fine in version 19w40a.
Suddently trees in general need a lot of bonemeal to grow... Like stacks of it...
What I expected to happen was...:
Plant a tree and it grows. Faster with bonemeal
What actually happened was...:
nothing, they wont grow, even with two stacks of bonemeal nothing happens.
Steps to Reproduce:
1. Get to buttom layer
2. Place dirt
3. Put birch sapling on it
4. Add bonemeal
5. Nothing happens
Linked issues
Comments

There shouldn't be anything nearby preventing it to grow. Tried moving the torches around the dirt further away, with no effect. I can see that it has updated to 42a, but i havent tried the birch. Oak can grow in the same setup..
Thank you for your report!
We're actually already tracking this issue in MC-163403, so I resolved and linked this ticket as a duplicate.
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Are there any blocks placed near the sapling? They might prevent the tree from growing.
Trees are growing fine for me in 41a, even at y = 1.