Not an answer to your question, just a bit I had read about RW and RR that some might find interesting.
Rockwool vs. Rapid Rooters
I did this little experiment to see if my recent switch from Rockwool (RW) to Rapid Rooters (RR) was really worth it. I have gotten 90% or so success with RW in the past and enjoyed the low cost of RW, but I hated the prep time of soaking and treating the RW as opposed to something I can just pull out of the bag and use.
The following clones were taken on June 22:
20 - 4" clones from strain 'Big' into RW
10 - 8" clones from strain 'Big' into RR
10 - 4" clones from strain 'Black Domina' (BD) into RR
The RW was soaked in low pH water for 24 hours, then rinsed with clear water and treated with a Schultz root helper (Can't remember name.)
Each clone was placed into a 3" basket and Hydroton was added to stabilize. The two trays of RW clones were filled up about 1/3 of the way and I added a small circle of soaker hose to aerate the solution. They were placed 6" away from a single 4' floro.
The tray of 8" clones in RR was filled to the same depth and no soaker hose was added. The canopy was about 6" away from a single 4' floro.
The tray of BD was filled and soaker hose added. Placed about 10" away from floro.
All clones were treated with Vita-Grow Anti-Wilt and two trays were placed under a single 4' floro. (So two shelves, a single 4' bulb for each shelf and 20 clones per shelf.)
Here are the results as of July 3 (11 days later):
Tray #1 (Aerated)
Of 10 - 4" Big clones in RW, 1/10 has roots coming through the RW but has not made it out of the basket. 4/10 have signs of succesful rooting but have not permeated the RW. 3/10 have no signs. 1/10 is of questionable health. 1/10 has died.
Tray #2 (Aerated)
Of 10 - 4" Big clones in RW, 1/10 has roots coming through the RW but has not made it out of the basket. 6/10 have no signs. 2/10 is of questionable health. 1/10 has died.
Tray #3 (No aeration)
Of 10 - 8" BD clones in RR, 7/10 has roots coming through the RR and most have atleast one root 1" outside of the basket. 2/10 have no signs. 1/10 has died. However, one of the ones with roots will not make it. After pulling out of the basket, many white healthy roots were pretruding from the RR. (See photo.)
Tray #4 (Aerated)
Of 10 - 4" BD clones in RW, 10/10 has roots coming through the RR and have several roots atleast 3" long outside the basket. New growth has also been noticed indicating readiness for more light and nutes.
So Tray #4 was by far the most succesful of all of them. But, since this wasn't very scientific many factors could have affected the outcome.
#1 Tray Placement. Both RR trays were placed closer to the floor. The air is cooler and could have decreased transpiration enough to help out root formation. A better setup would have placed the BD 4" tray on the top shelf next to a tray of 4" RW clones. This would have allowed for more similar conditions.
#2 Light distance. The RW clones were closer to the light than the BD clones. The lower level of light for the 10 - 4" clones could have helped root formation by not stressing them as much.
#3 Strain. The 10 BD clones may have been a strain that is easier to root than the Big. Though I have rooted many clones of Big in the past, this was my first experience with BD.
#4 Cutting length and condition. 10 Big clones were cut at 8" and 20 clones were taken at 4". The 20 clones were healthy tops while the 10 - 8" ones were taken from slightly woodier stems and shaded undergrowth. But, the 10 larger ones formed more roots sooner even without aeration.
#5 Water quality. I never changed the water the entire time. Just topped up.
Many other factors could have played in as well but the results are clear to me: Even in unaerated conditions with large sized clones, the Rapid Rooters have out performed the Rockwool. The high levels of abuse and stress they suffered still didn't stop most from rooting and at this point have given me a 90% overall success rate if no more die.
Rockwool success is at 90% and Rapid Rooted success is at 90%. Even though the success rates are the same (at this point), the RR have provided better results sooner. The higher cost of the RR is justified by the increased speed that roots form. If I can get the clones into a larger system sooner, the better off they'll be. I can use the extra time saved to clean the cloning area and prep for the next round of clones.