1 watt of pumping power per gallon of solution.
I think it was a guide or seedbank that recommended that as a good average. Of course if you have a large bubblestone that requires more pressure, long tubes and such you might go for a little more.
Grafting can transfer genes between two plants, creating new genes.
https://www.nature.com/articles/nature13291
And it have been done with many plants already for example fruit plants and of course Cannabis as well.
For example hops with high amounts of THC and CBD exists out there. It's...