Evaluating ‘Scientific’ Claims

Whenever I give talks to landscapers or gardening groups some of the most common questions that come up deal with various products promoted to provide ‘miracle’ results in the garden.  These are usually various soil amendments; fertilizer additives, bio-stimulants, mycorrhizae, and the like.  My initial reaction to these inquiries is, “What does your current basic plant maintenance look like?”  Are you mulching? Irrigating when needed? Fertilizing if needed? Pruning properly?  Have you matched the tree to the site conditions?

As a culture we seem oblivious to the tried and true and gravitate to the quick fix.  Look at late-night infomercials for weight loss products.  Hoards of people are willing to shell out $39.95 (plus shipping and handling) for a bottle of pills guaranteed to miraculously ‘melt away pounds’.  Apparently “Eat less and exercise more” is a tougher sell.  For garden products claiming to produce bigger, better plants there is sometimes a grain of scientific rationale and for a few, such as mycorrhizae, there are specific situations where they can be a benefit.  Nevertheless the basic rule of caveat emptor is the best guide.  Remember, just about anyone can get on PowerPoint and develop some slick looking 3-D bar charts and put together a glossy brochure or cool-looking website. Here are some things to consider when evaluating ‘scientific’ claims.

English 101

Words such as more, greater, bigger, faster are comparatives.  They compare one thing to another.  They need to be followed by a ‘than something’.  Without an object they are meaningless.  Advertisers use this all the time: “New Shill gasoline gives your car more power!”  More power than what? Not putting any gas in your car at all?  So what does a claim that a stimulant produces ‘more and stronger blossoms’ really mean?

What’s compared to what?

Some manufacturers go further and compare their product to an untreated control.  This is a step in the right direction but can still be somewhat misleading.  A common example is various bio-stimulant products, which often contain various enzymes and nutrient elements.  Compared to an untreated control these may indeed improve plant growth.  But is this due to a unique and patented blend of dung beetle excrement and papaya extract or simply the fact that a product contains essential plant nutrients?  A better comparison would be to compare plants receiving the miracle product and plants receiving a conventional (and less expensive) fertilizer containing similar nutrient elements.

The bottom line, as always, is if something sounds too good to be true, it probably is.  Before reaching for an exotic concoction of eye of newt and wing of bat, consider the basics of site selection and landscape plant management.  Chances are there is a lot more to be gained from mundane matters such as putting the right tree in the right place than from trying to remedy the situation by sprinkling some magic dust over the roots.