Rooting Cuttings in Water.
Rooting cuttings in water is the most simple and effortless method of rooting clones I have personally used. Cloning (by traditional methods such as soil, rockwool, etc.) seems to go something like this: Half the people who try it have phenomenal success right off the bat, and the other half have very little (or no) success whatsoever. I fell into the second half of would-be cloners. The half with very little success. In fact, my success rate was exactly 0.5% (1/2 of 1%). Out of my first 200 clones attempted, I had exactly one root. This clone happened to be one that fell behind a box where I was working and I only found it after I had already put away all my cloning "equipment". I didn't feel like getting all my stuff back out, so I put it in a cup of water in my window sill... a week later I had roots. I had always heard and read of people doing this, but it sounded far too simple and, quite frankly, beneath the "plant scientist" I had become so I never tried it. Let me just say that I have no problem at all rooting nursery crops (boxwood, holly, nandina, euonymus, etc.) in the more traditional ways, but for whatever reason I simply cannot get Cannabis to root in these ways, and once I put away my pride I was able to get results.
I didn't really find any "science" about rooting in water, so I set out to find some of my own. None of what follows is "real" science, but it is a good starting point for those who have trouble cloning in soil and want to try a different method. So, with no further ado, here are a few things I have learned:
1. Use only tap water. Any other water tried (distilled and reverse osmosis) tended to only form callus, and no roots (when roots did form, there was low number of roots per cutting (1-2), and low percentage of cuttings rooting (generally less than 20%). Well water might be even better than tap water (since it will have all the minerals, but none of the chlorine), but well water was not available to test.
2. In general, using rooting hormone will not give you any significant improvement in time to root or number of roots per cutting over control. In fact, any treatment below ~150 ppm IBA (basal soak or total immersion) seems to inhibit the number of roots per cutting but not affect the time to rooting.However, in one experiment attempted (thinking the rooting hormone percentage would be overkill), a one minute basal soak in a 4,000 ppm Indolebutyric acid solution (in water) (water soluble salt of IBA/Hortus USA) improved number of roots per cutting (from 3.6 to 28.4) and time to root formation (from 8 days to 6.5 days) over control in Critical Jack Herer by Delicious Seeds, and Critical by Royal Queen Seeds. Results with other strains were inconclusive, but it would be worth doing your own experimenting as it is likely to work with other strains as well. Needless to say, the more roots a cutting has when you plant it, the better off (in general) it will be. So this treatment is worth exploring further should anyone choose to do so.)
3. Use optimal basal cut angle for method used. If using any type of rooting hormone treatment, cut stem-base of cutting at 90 degree angle (straight across). If not using any form of treatment, and rooting with just water, cut stem-base of cutting at typical 45 degree angle. It was found that with any form of treatment, 90 degree cuts will root faster (sometimes by as much as a week) most of the time than 45 degree cuts. Without any treatment, 45 degree cuts will root faster than 90 degree cuts most of the time.
4. Change the water only as frequently as needed to prevent biological film (slime) buildup. Changing the water too frequently seems to increase the time it takes for roots to form.
5. Purge your water pipes before collecting your tap water. When filling whatever container you are using with tap water, simply run your faucet for several minutes before collecting your water. This will bring water from the main water line to your faucet rather than water that has been sitting in your homes water pipes. This seems to decrease time to root in my house. It could just be my water pipes, but surely there are others out there that will be affected too. I assume it has something to do with something leaching from my pipes into the water, but I really don't know.
6. Keep light out of the root zone by any means necessary. Light is a well-known inhibitor of adventitious root formation.
7. Use florescent lights, and give cuttings a dark period. The dark period doesn't seem to make a significant difference in general, but it does seem to speed the time to root formation in some strains... so I use it every time.
8. Expect to wait a minimum of one week before seeing roots. Don't rush it. Most strains take closer to 10-12 days, but some will root as quickly as 6-7 days.
9. Patience is key. Again, don't rush it. Excellent success has been had rooting cuttings in water. However, some cuttings will occasionally fail to root. It just happens. As you probably know, rooting ability is very dependent on strain. Some are very easy, some are next to impossible. Be patient and you will have results.
9. Transplant to soil when at least one root is .5" (1/2 inch) long. Place the transplanted plants into the same conditions they were rooted in (same light and temperature) for at least an additional week before attempting to acclimate them to full-strength vegetative lighting. Obviously if you are not growing in soil, transfer to whatever medium you are growing in. I only grow in soil so I can only speak for soil.
10. Type and size of container didn't seem to affect results. Everything from 2oz plastic cups, to large plastic containers (Tupperware/Rubbermaid type containers) have been used with approximately the same results.
There you have it. The results of my extensive experience and testing with rooting cuttings in tap water. It is the only method I use to clone Cannabis. If you have trouble rooting in the more traditional ways, please give this a try using the guidelines above. And, by all means, please don't ever stop experimenting and adding to the Cannabis propagation body of knowledge.
Anthony C
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