Superthrive is one of those product that probably get used unnecesarily half the time. It's real strength is in having Naphtyl Acetic Acid wich is an plant hormone that stimulates root growth. The 50 vitamins are, like multi-vitamin tablets, largely going to be wasted except in certain circumstances.
It does have a use for stressed plants or when transplanting sensitive plants and is also used for fast growth such as hydroponics. I'd just keep it a a pick me up for problems rather than all the time, in the same way as epsom salts tend to only get used when there's a magnesium deficiency. Humates have the same reputation for improving growth etc, and whilst I'm finding slightly improved roots when I've used them, the plants I've just used compost for look just about as good/variable.
In short, I wonder whether it's a cae of fixing what's not broken anyway.
