I plan to germinate a few auto-flower seeds in rockwool cubes. Does the seed have a top and bottom or does it matter the orientation of the seed when placing in the rockwool?
The dimple is top
I just want to confirm seed orientation, you are recommending that the dimple of the seed face. I am reading others suggest just the opposite. Are there differing opinions about or is the just only one recommended way?
Pointy end down, dimple at top.
The tail that pops out will come from the pointed end, this as @AAA said, dimple is the top. Some people point it opposite so the tap root only has to curl once instead of twice. Truth be told it really won’t matter for survival. The roots search down and out because water search and gravity and the top searches for light. It’s just much easier on you to face it the way it needs to go.
In nature seeds will fall in almost any direction, mostly on the side.
If you look at germinated seeds you see they naturally curl back down toward the dimpled base.
Planting with the dimple down, point up, allows the taproot to naturally curl down and when the time is right it will push the top of the plant above ground. The benefit of this is that the seed husk almost always will get stuck in the dirt and left behind because it is split open in this position. V
Oriented the other way it rides up with the seedling and you get helmet head seedlings.
Have not had a stuck husk since I started placing the seeds dimple down, tip up.
Just my method…others may do it different.