BrianBay9

Hi folks,

Those of you who know me, know that I've always had a healthy skepticism of highly marketed, but unproven products like Superthrive. However, people that I respect swear by the product despite the lack of scientific evidence to its efficacy. With the new nursery I've found myself in the position of being able to set up a decent experiment to prove to myself (and perhaps others) that Superthrive (ST) either works, or doesn't.

I decided to focus on two label claims for ST. In the first, the ST label claims in provides a significant improvement in growth for transplanted seedlings. In the second, it claims that it improves propagation. I chose to interpret that as improving the process of taking cuttings.

I specifically did NOT choose to continually water plants, with and without ST because of the logistical burden that would place on a nursery operation. Also the statement on the ST label that says ...."As ST plants use more nutrients for growth, they may require the use of more fertilizer than other plants"...seemed highly suspect (More fertilizer = more growth?)

Experimental Design:

Each species of cuttings or seedlings were done at the same time. For each, half of the plants were soaked in ST, and half in water. The ST concentration was at label recommendations (1 tablespoon per gallon). The plants were soaked for an hour before planting. Plants or cuttings from each species were planted in the same soil mix, and same size pots, then set out in alternating rows (ST, not ST, ST, not ST, etc). From then on, all plants will be treated the same regarding watering, fertilizing, sun exposure, etc.

For seedlings, so far I have:

26 hackberry
56 boxwood
84 J Black Pine
100 Sequoia
100 bald cypress expected soon.
Total of 366, each group half with ST, half without.

For cuttings, so far I have

86 olives
26 junipers
28 chinese elm
52 dawn redwood
Total of 182, each group half with ST, half without

I would prefer 100 or more with and without ST for each species, but that's life. I expect any differences to be seen between planting and our mid-summer heat dormancy, since the treatment with ST was done only once. Either way, I will report back on this thread with numerical data and hopefully pictures of the results. I will be looking for differences in survival rates, and differences in growth (height, fullness, whatever).

I realize there are many other ways that people use ST, but I can only do what I can do. This experiment will put this issue to rest for me, but you all can make your own judgements.

Cheers
Brian

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There's a difference between taking your art seriously, and taking yourself too seriously.

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