I’m certain I’ve stated this elsewhere, but without a doubt, orchid growers are second only to backyard marijuana growers when it comes to trying to find that “holy grail” additive for making their plants grow better. Unfortunately, that search for “magic additives” can also make them gullible to advertising and marketing ploys that result in money spent for no gains.
In most cases, it’s not that those marketers are lying exactly, but the conclusions they make from their “evidence” or explanation of benefits can be suspect. Let’s take, for example, SUPERthrive “The essential vitamin solution” to “secure your transplants, revive stressed plants and produce abundant yields”.
As far as I can tell, this proprietary formulation’s primary ingredients include naphthalene-acetic acid (NAA), a synthetic root-growth stimulant, and vitamin B-1 (thiamine), and easy-to-absorb source of nitrogen and carbon. Does the product work to stimulate plant growth? Sure – if it’s fresh (synthetic hormones like NAA are notoriously unstable if warmed or exposed to light, so can break down quickly in-transit or even on the shelf at your local store). Is it the magic additive the labels and advertising implies? No; any decent stimulant can be helpful, but I see nothing “magic” here. Personally, I think that if you want to go with a synthetic product, Dyna-Gro’s KLN, containing both NAA and a second synthetic hormone, indole-butyric acid (IBA), is more cost effective, although it still suffers from degradation, and if you want the “Cadillac” of stimulants, Kelpak is the only choice.
Another “magic additive” that has been pushed a great deal is Mega Thrive. I was recently asked about the utility of using the product “Mega Thrive” on orchids. Having never used the stuff, I did some digging, and this is what I have concluded:
Mega Thrive is what I would call a “specialty fertilizer” with a 3-0-3 formula, containing nitrogen (2.99% urea, 0.01% ammoniacal), potassium, boron and molybdenum, and is intended for foliar application. Its stated goal is to facilitate the circulation of auxins and cytokinins within the plant, which is basically what controls all growth processes, through the application of boron and molybdenum. This is actually not new technology, as the use of such supplements has been employed in commercial nurseries for decades. Most often, such supplements are necessary only when the nursery, in an effort to be as economical as possible, has a routine feeding regimen that employs urea only, so must periodically supplement that with additives. Hobby orchid growers tend to use fertilizers that are fairly complete, precluding the use of those additives. Nonetheless, let’s look into the Mega Thrive claims and assess their veracity:
Urea is the preferred form of nitrogen for foliar uptake, while nitrate and ammonia-based nitrogen is preferred for root uptake, so the product’s use of urea seems appropriate for a foliar product. Likewise, both boron and molybdenum play important roles in the circulation of auxins and cytokinins and are essential to plant health. So, on face value those claims seem quite plausible, but let’s look a little closer.
As far as foliar feeding is concerned, we must not forget that many orchids have thick, waxy, cuticle layers on the leaves, intended for water conservation. Those layers slow-, if not altogether prevent contact of solutions with the cells (plasmodesmata) that would allow such uptake, rendering foliar application to be less effective than it might be with other plants.
As stated right on the Mega Thrive label, if overapplied, boron can be toxic to plants, and that plants treated with molybdenum may be toxic to birds and mammal eating them.
It seems to me that if you are already using a complete fertilizer formula, such as K-Lite, MSU, Jack’s Classic or the like, you are already providing plenty of those nutrients, making it potentially risky to supplement them further. Plus, if you’re using Kelpak Superior Plant Growth Stimulant as recommended, you’re already facilitating the accelerated flow of auxins and cytokinins in the plant – without the added risk of toxic metals – and it can safely be used on all plants.
We can also look at it from an economic standpoint:
Mega Thrive retails for $27.50 per quart plus $13.49 shipping (Amazon – best price I’ve found, 12/14/2020), so that’s $1.28 per ounce. The recommended application is 3 ounces per gallon every two weeks, so the annual cost comes to about $100 per applied gallon per year. Kelpak is $37 per liter, including shipping, so that’s a lower unit price at $1.09 per ounce, but the recommended application is 1 tablespoon (1/2 ounce) per gallon per month, making the comparative cost about $6.54 per applied gallon per year.