Your doing it wrong if you firmly believe this, you should not be losing 50% of your clones.
Yes and No.
Depends on the plant. I prefer to use jiffy plugs with tap water in a tray with rooting hormone with a dome with a temp controlled heating pad with a bit of air flow under either MH or LED (at a decent distance). I use a laser temp reader to check leaf top temps.
I have 6 mothers, 4 indica and 2 sativas, all very different. They are the results of growing out bag seed from a year's worth of buys, which in turn gave us a shitload to choose from. Kept the best of course.
I'll grab a dozen at a time from each plant and put them in a single tray, so the conditions are identical.
3 of the indicas will root WELL in under 10 days, about a 95% success rate. 1 indica will take about 30 days, with about a 60% success rate. The slower one is my favorite, so I'll keep at it.
1 sativa will root WELL within about 20 days, with about an 80% success.
1 sativa SUCKS! It will take up to 30 days to root, with about a 5% success rate. But the bad ones will stay green and even grow, which means I waste time waiting for them before they fall over and die.
So, I have choices. 1st choice is to flower the mother and stop cloning that plant. Other choices are to vary the conditions, rooting gel VS powder, heat or humidity or light or air flow, etc. Or I can setup my home made cloning machine, but why? I have enough choices and the sativa I have that does well is kick-ass.
I'm flowering it.
Please don't assume a person is doing it wrong if their success rate does not match yours, unless you gave them the mother.