A while back I took an interest in using root pruning chemical products on a trial basis with Cannabis and other plant material. These products use a copper base and are sprayed or painted on the inside of the pot to achieve root-tip dieback inducing profuse secondary root branching. As far as I know, root pruning products have never been evaluated by the horticultural community, amateur or otherwise on Cannabis. Past experience with yard plants and a few Cannabis plants was successful, so, I decided to commit my entire garden to its use and see what might happen.
I decided to try one such product called Griffin's Spin-Out on various strains, aka copper hydroxide suspended in a carrier, painted on the inside of the pots to achieve root tip pruning. The commercial trade has been using copper compound paints for root pruning for many years, and thousands of professional studies have been conducted on the merits of chemical root pruning. Rather than go into the details, I'll refer you to a link of the product and what it does: click here
The following photo shows one gallon pots that have been spray painted with two coats of Griffin's Spin-Out. My current plan is to sex in these pots at around 3 weeks (if growth is good), and then upcan to untreated 3 gallon pots to finish.
Just took this pic of my seedlings that have emerged from the soil and are anywhere from 3 days to 8 days old. The plants used for evaluation consist of (5) TFD Thai-tanic, and my crosses: (4) C99 X H, (4) Peak19 X H, and (4) C99 X Peak19. 17 seeds sowed, all germinated. They are under a 400W MH, Super Sun hood.
The larger plant in the foreground is an unknown (in an untreated pot) that is about 2 weeks old, topped two days ago which if female will have 4 main colas. A few seeds became strays on the sorting table, and if I had to guess, it's a C99 X Peak19 based on its leaf/node structure. I started it early to test my new soil blend's merits, as well as to test for damp-off as I only used solarization to sterilize my soil mix, not heat, as I normally do.
What a difference a week makes, eh? Two weeks after the faves popped the soil's surface, thought I'd take a pic. The largest (and first germed) faves have spreads of up to 13.25"/34cm... with the smallest fave (and last one to germ) about 5"/13cm across. The smallest is in the foreground holding the Chills hemp papers (the best papers IMO) and the larger ones to the left.
It's about time to go 12/12, especially with the C99 X Haze as this cross has long internodes and will surely end up like trees. They are turning out very sativa dominant.
Thai-tanic, C99 X Peak19 and P19 X Haze are very well behaved, having beautiful profiles. The plant in the left foreground (Haze X Peak19) is now 20" (51cm) across, the late germing kid (Haze X C99), sitting on a high chair in the foreground, is 8" (20cm) across. He got a toppin' a week ago or so ago.
Plants are very healthy requiring watering twice a day with the exception of the smallest plants. Side panels have had to be expanded 3 times since the last shot as the garden is expanding rapidly. We got Skunks around the Bendejo farm... Love dat aroma! You can see some Skunk influence in the Thai-tanic. Very nice cross so far.
All plants are doing extremely well in the Spin-Out treated pots. In fact, the only plant that is pouting is the one in the untreated pot. Maybe he's jealous...
Photo is a little dark...a wine bottle is in the foreground for reference.
Week four, 12/12 started 4 days ago. The growth continues at an excellent rate. Maintenance is quite high due to the small pots and very warm weather which is causing temps to peak and hold at a high of 94F in spite of my efforts to keep it down....not good.
Wide angle shot (which skews the large size of the plants and spread of the garden), flash only. Garden is now 20 s.f. where it started at 9 s.f. in week one. Plants are crammed into the space of 20 s.f. Lights have to be raised about 1" to 2" everyday now.
Today I dumped all plants showin' any nasty lil' balls after six days at 12/12. Of 18 plants started, nine are female (which REALLY is gonna be a space problem for me!), six are male and three undetermined. The attached photo shows a representative profile for six males that were destroyed. The two on the left are TFD Haze X Peak19, the one on the right being C99 X Peak19. Tallest plant is 27" (66cm) tall not counting the height of the rootball. Yardstick is in the middle for reference.
Notice the middle rootball with a few exposed roots? I'll explain later with another photo.
As you saw in the previous photo, roots are not spinning out.
The following pic is a closeup of the middle plant's rootball. With the tip of my finger, I knocked off about a cm of soil (in depth) in a small area located in the middle of the rootball so you can see what's lies behind the rootball's outside perimeter. Keep in mind these rootballs are quite small - 6"/15cm in diameter and 6" tall.
Here's a closeup of a rootball showing an extremely fibrous rootmass after I shook off as much (fairly dry) soil as possible. The mass is very dense with no spin-out indicated at all. Fibrous mass stretched about a foot long when held up. Large white root in the middle looks like the original taproot. Again, the importance, for vigor's sake anyway, of starting a seed in a deep, tall pot... as reflected in my germination archive.
Plants are definitely potbound although not showing any indication of such except for the need to be thoroughly watered twice a day.
They will be upcanned to untreated three gallon pots tomorrow.
Here is a link that shows increased production for flowering plants. Doesn't mean that cannabis will have the same results regarding increased flower production, then again, doesn't mean it won't. The conclusion drawn on this premise will take some study and time. Plants' reaction is based on simple botany.
Here is a PDF file (you'll need Adobe Acrobat) that reflects four species of flowering plants that showed a 55% to 160% increase in flower production while grown in copper hydroxide treated pots. Open the file when and if prompted regarding saving it to disk or else save it if you'd like to read it later. click here
Here is another male (O.Haze X Peak19) found this morn that will soon be destroyed. It is 31" tall (with pot height)...shot was taken overhead. It has a strong indica influence from the Peak19. In fact, it looks almost identical to the regular Peak19 I grew last year. Has very dark, wide leaves and leafsets, especially at the lower levels (correct color being evident under normal room lighting).
Destroyed another male, the only one in an untreated pot. Pot-bound condition with typical rootball spin-out is noted.
Plants love the Griffin Spin-out treatment. Am having to water the three gallon pots everyday now and having to top some plants due to the vigor and heavy Haze influence. This garden is sativa dominant with the exception of a few faves, which are taking on a typical indica/sativa hybrid profile - the C99 X Peak19. Topping during this late stage of the game is not my preferred method of plant height control and I don't recommended it to most folks, but, I don't need or want the aggravation of fighting my garden's height even if it means a sacrifice in yield. Some plants are already 46" tall while approaching only the third week of 12/12 this Sunday. Shyste burgers, there's a whole lot of stretching left!
Here's a partial garden shot reflecting all plants upcanned to untreated three gallon pots. Would have taken a full garden view if possible, but, the Bendejo farm is getting a little cramped, to say the least, and the lens won't handle the expanse or height from where I'm (restricted to) as I shoot the photo.
Three weeks at 12/12 and the plants are just now responding with a strong flowering response. Getting nice little balls of popcorn on dem dar faves! Here's a partial garden shot with a C99 X Peak19 in the middle. This is turning out to be a great cross regarding profile, vigor, and flowering. Thai-tanic is also very nice but being practically a pure sativa, is a PITA regarding its long internodes and long petioles. I mean, the damn plants are like 24" across leaving my garden really cramped. Garden is around 20 s.f. The vigor and health of the plants is excellent with the only drawback being very frequent watering while they were in one gallon pots.
Got my custom soil blend a little "hot" this go-around but that's another issue. I've had to either cut out any and all chemical tweaks or limit it to a select few.
This is a shot of some of the garden at four weeks flowering. This is a very sativa-dominant garden so I'm wrestling with stretching and doing alot of topping, even now. There are two Thai-tanics barely visible on the left with Haze crosses showing as the leggy, fluffy buds plants worked around the perimeter. The only plants that I think will give me thick, heavy colas are my C99 X Peak19 crosses. Their parents produced heavy colas....and are already showing heavy trichome formation. Thai-tanic being as pure of a sativa as you can get with a tad of indica thrown in from the Skunk #1, has a great profile, but man is it leggy. Buds are quite dense for a sativa.
C99XP19 cross. Excellent profile, should be ready in another two weeks. This fave is six weeks old. There's some leaf curl due to excessive heat about two weeks ago... oh well.
Just an update with a pic of my first harvested plant from the experiment to show her health, yield and all. This is a C99 X Peak19 harvested just shy of eight weeks flowering. Bottom line? The experiment was a success!