This was published in Stemma Magazine:
Superthrive or Superjive
The question regarding the value of Superthrive as a miracle tonic for plants is often bandied about in horticultural circles. Over the years, I had read claims that ranged from, "I put it on my plant, which had never bloomed, and it was in full bloom the next day." to, "It was dead - I put Superthrive on it and the next day it was alive and beautiful, growing better than it ever had before." I decided to find out for myself.
If you look for information on the net, you will probably only find the manufacturers claims and anecdotal observations, both so in want of anything that resembles a control. Though my experiments were far from purely scientific, I tried to keep some loose controls in place so that I could make a fair judgment of its value, based my own observations. Here is what I did, what I found, and the conclusions I made about any value the product Superthrive might hold for me.
On four separate occasions, I took multiple cuttings of plants in four different genera. In each case the group of cuttings were taken from the same individual plant to reduce genetic variance. The plant materials I used were: Ficus benjamina, (a tropical weeping fig) Luna apiculata (Peruvian myrtle), Chaenorrhinum minus (a dwarf snapdragon), and an unknown variety of Coleus. In each instance, I prepared cuttings from the same plant and inserted them in a very fast, sterile soil. The containers containing half of the cuttings were immersed/soaked in a Superthrive solution of approximately 1/2 tsp per gallon of water to the upper soil line. The other half of the cuttings were watered in with water only. In subsequent waterings, I would water the "Superthrive batch" of cuttings with a solution of 10 drops per gallon and the others with only water. The same fertilizer regimen was followed on both groups of cuttings. In all four instances, the cuttings that I used Superthrive on rooted and showed new growth first. For this reason, it follows that they would naturally exhibit better development, though I could see no difference in overall vitality, once rooted. I can also say that a slightly higher percentage of cuttings rooted that were treated with the Superthrive treatment at the outset. I suspect that is directly related to the effects of the auxin in Superthrive hastening initiation of root primordia before potential vascular connections were destroyed by rot causing organisms.
In particular, something I looked for because of my affinity for a compact form in plants was branch (stem) extension. (The writer is a bonsai practitioner.) Though the cuttings treated with Superthrive rooted sooner, they exhibited the same amount of branch extension. In other words, internode length was approximately equal and no difference in leaf size was noted.
As a second part to each of my "experiments", I divided the group of cuttings that had not been treated with Superthrive into two groups. One of the groups remained on the water/fertilizer only program, while the other group was treated to an additional 10 drops of Superthrive in each gallon of fertilizer solution. Again, the fertilizer regimen was the same for both groups. By summers end, I could detect no difference in bio-mass or vitality between the two groups of plants.
Since I replicated the above experiment in four different trials, using four different plant materials, I am quite comfortable in drawing some conclusions as they apply to me and my growing habits or abilities. First, and based on my observations, I have concluded that Superthrive does hold value for me as a rooting aid, or stimulant if you prefer. I regularly soak the soil, usually overnight, of my newly root-pruned and often bare-rooted repots in a solution of 1/2 tsp Superthrive per gallon of water. Second, and also based on my observations, I no longer bother with its use at any time other than at repotting. No evidence was accumulated through the 4 trials to convince me that Superthrive was of any value as a "tonic" for plants with roots that were beyond the initiation or recovery stage.
Interestingly, the first ingredient listed as being beneficial to plants on the Superthrive label is vitamin B-1 (or thiamine). Growing plants are able to synthesize their own vitamin B-1 as do many of the fungi and bacteria having relationships with plant roots, so it's extremely doubtful that vitamin B-1 could be deficient in soils or that a growing plant could exhibit a vitamin B-1 deficiency.
Some will note that I used more of the product than suggested on the container. I wanted to see if any unwanted effects surfaced as well as trying to be sure there was ample opportunity for clear delineation between the groups. I suspect that if a more dilute solution was used, the difference between groups would have been even less clear.
It might be worth noting that since the product contains the growth regulator (hormone) auxin, its overuse can cause defoliation, at least in dicots. The broad-leaf weed killer Weed-B-Gone and the infamous "Agent Orange", a defoliant that saw widespread use in Viet Nam, are little more than synthetic