I’m a total Dum Dum so I got questions about farming that farm school doesn’t show or mention (Organic Crops)
1st question can I Slope Chisel the bottom of the block and place water there and till the same soil I chiseled?
2nd Quistion Can I use any color of gleam light as a light source? & how far does the gleam have to be to count as light?
3rd Quistion will my crops die if I have them completely submerged in water
I’ll have more later cause me dum dum Boop!
Slope chisel from below and plant on top not sure would have to try 
any crop will do youl get it back if you wack it again (the crop).
As far as water goes it should work. If you can plant on top of it.
(Know for sure you can plant on a sloped top 
)
As for gleam light it works depending on the color you use. White being the the one that is brightest.
If I remember correctly i had it about 2 blocks above my crops (enough space to freely walk).
And each line 2-3 blocks appart. But my farms wher mostly design builds.
But thats all i can tell you from memory not sure where i left my screenshots.
Is it the rice one? I know grows best in flowing water. Submerged 
not sure
I dont believe the bottom of the block interacts when used to grow crops. You could experiment with that if you’d like to anyway. For gleam, I do believe any gleam will work as long as there is space for the crop to grow. Single row right above the plants is what I did, with some chisel work on them suited for my application. No idea about drowning your crops, might have to try that out lol