I'm a rockwool guy, and here's my process.
1. Take cut. I do NOT cut at 45 degrees. I cut straight across to keep the wound size minimal. I take larger cuts than most, only from the middle of the plant. Main tips root faster, but grow slower. Props to Woodsmaneh for explaining this elsewhere on this board.
2. Soak cutting in R/O for 24 hours. I will never believe anyone telling me this does not make a difference. It's night and day. I don't even check the PH.
3. Soak Rockwool in R/O for 4-6 hours, then flush it through thoroughly with R/O. Again, I don't even check the PH.
4. I make a single scrape about an inch long of the outer layer of the stem with a razor blade, then insert into Rockwool.
5. Mist dome (not cutting), and cover.
6. Open vents 25% after 2 days, and another 25% each following day until the vents are completely open. Two days later they're ready to start acclimating to room humidity, and that's when the roots show up en masse.
Now a couple of notes. I'm sure I'll catch hell for not PHing either the water my cuts soak in or the soak for the Rockwool. Let me explain. It has been my experience, and that of growers more experienced than I, that the primary affect of PH on Cannabis is an increase or decrease in the plants ability to uptake nutrients. With a little consideration, it seemed irrelevant to mess with PH when there's no roots to uptake any nutrients anyway. By this logic, PH would become a concern AFTER roots were present, but not before. This logic seems to apply in practice as well, because I haven't considered PH when it comes to cloning for years now, and I have good success.
Now on to the Rockwool, and soaking in UN-PH adjusted water. Strangely, it seems uncommon knowledge that a PH below 5.5 begins to actually break down the Rockwool itself, and the tiny air pockets affected by this are absolutely vital to your cuttings ability to grow roots. What we're trying to accomplish here is to purge the cube of the remnants of the production process. While a lower PH speeds this process, it's really easy for those less experienced with Rockwool to whip up a tub of water brought down to like 4.0 - 4.5 and drop a bunch of cubes in. The idea is that everything is fine because after a few hours the PH is reading 5.8 or 6.3 or something. What isn't accounted for is the two hours that the PH was too low, spent literally dissolving the rockwool.
Personally, I don't give a crap what PH my rockwool is, because I don't actually grow in it, just root and germinate, and as it happens, my plants don't need any nutrients until they've got roots that extend out of the rockwool. R/O water, regardless of PH, is caustic enough to leach the unwanted out of the cubes. At this point I'm feeding the roots (PH 5.2 - 5.3, low N and Hi P) and keeping the rockwool dry anyway, so PH never becomes relevant to the rockwool. Honestly, success is only marginally better in soaked and rinsed rockwool than with cubes straight out of the bag.
Another note on RH and the dome that I have come to accept, although not fully understand. One day I discovered that a pile of discarded, presumed failed clones were rooting prolifically in my trash bin, while others (cut on the same day) that had been living in a dome, were struggling and showing no signs of root generation. This led me to experiment with optimal RH for cloning. What I found is that new cuttings need at least a couple of days of full on, as close to 100% as you can get, RH to provide a buffer for the stress of being cut, and cut-off from it's supply. What I found, was that clones that are weaned off the humidity after the first couple of days, root much faster than clones that just live in the dome until they have roots. I accept this, and rationalize it by telling myself "why the hell would it bother to grow roots, if it can get all it's moisture from the air?". I have no idea how accurate it is, but the presumption is that it never goes looking for a drink if it never gets thirsty. Keeping the RH just a tad lower than they want seems to motivate rooting.
Again, all of this is just my own personal observations. As usual, your mileage may vary. I'm no "master grower" (whatever the hell that means), but I have been doing this for many years, and the above continues to work.
