You're strolling past the booths at a farm show when a new product grabs your attention. Maybe it's a soil additive with marvelous claims: enhanced growth, improved nutrient absorption, more beneficial soil bacteria. Buy this product and boost your yields, you're told. The promises are accompanied by convincing endorsements from farmers.

It sounds intriguing, you think, but is it for real?

Every spring nontraditional fertilizers and soil products appear, promising wonderful results, says University of Minnesota retired soil scientist George Rehm. Over the years, he has seen a host of biological stimulants, enzymes, bacterial additives and other novel products come — and quickly go.

His advice: Before you write a check, check it out. “Will they perform as advertised? Are they registered for sale? Have they been tested? And finally, are they worth the money?” Growers should be skeptical of unusual product claims or promises they haven't heard before, he says. “If it sounds too good to be true, it probably is.”

Rehm can name many nontraditional products that were touted in past decades, then vanished when their claims didn't stand up to rigorous testing. “Remember ACA, Asset and Amisorb? These products hit the market with fantastic claims about root growth and yield.”

Or AgraLife and Sea-Born Plus-F — products made from algae and seaweed, which were sold as biological stimulants. “It's interesting that many of the ‘stimulants’ that are supposed to do good things contain extracts of seaweed or kelp or fish or all three,” Rehm observes. “This is just one of the many mysteries of life!” Replicated trials at the University of Wisconsin and Iowa State University found that “AgraLife and Sea-Born Plus-F had no positive effect on yield,” Rehm reports.

Nontraditional products are often sold through testimonials, “with almost evangelical fervor,” says DeLon Clarksean, a certified crop advisor at Farmers Co-op Association in Canby, MN. And product testing is typically done by the company selling the product.

Testimonials, simple split-field trials, research summaries, news articles or fact sheets do not qualify as evidence of product efficacy, says Paul McNelly of the Minnesota Department of Agriculture, a fertilizer expert who reviews new product labels and claims.

So what kind of proof should growers look for?

You should see authentic experimental data from a land grant university or other reputable independent research agency, such as USDA, McNelly says. Trials must be properly designed and replicated. The tests should be done on the types of soils, crops and rotations typical of the region. And the data must be analyzed with appropriate statistical methods.

If a nontraditional product catches your interest, here are a few more questions you should ask:

Is the product registered for sale in your state?

Fertilizers and soil additives are licensed at the state level. Although the rules differ by state, registered products must meet minimum requirements designed to protect consumers, public health and the environment. Nontraditional claims must be substantiated by unbiased experimental evidence.

Is the product being promoted “off-label?”

Sometimes, a nontraditional product may be registered as a fertilizer, but quietly promoted for “off-label” uses, which are not supported by rigorous research.

Will the product be useful on your farm?

Growing conditions vary widely. So even if a nontraditional product proves useful in some circumstances it may not benefit your particular operation.

Growers should also look for consistent benefits, Clarksean says. “I've seen some pretty amazing results — once or twice — but not repeatable. It worked once and never worked again. But what people tend to remember is the year that it did work.”

Have you talked to the experts?

Growers faced with a marketing blitz can get help from many sources. Certified Crop Advisors, who sign a code of ethics, can provide an objective evaluation. Advice is also available from your county or regional Extension office.

9 Red Flags

  1. “Secret” ingredients
  2. High-pressure sales
  3. Testimonials
  4. Unusual product claims
  5. Few details about product performance
  6. Tests done by the company selling the product
  7. No well-documented research studies
  8. Product not registered for sale in your state
  9. Product being promoted off-label