If you want to have a greener thumb, keep those hair cliipings the next time you get a hair cut. Apparently, human hair is a good plant fertilizer.

The results of the study were detailed in a recent issue of the journal HortTechnology.

Human hair discarded from barbershops and hair salons can also be a nutrient source for plants when combined with other compost materials. But it had not yet been proven that hair could act alone as an effective fertilizer.

To test this, Vlatcho Zheljazkov and his colleagues at Mississippi State University compared the productivity of four plants, lettuce, wormwood, yellow poppy and feverfew, under four different treatments: non-composted hair cubes, a controlled-release fertilizer, a water-soluble fertilizer, and no treatment.

Results: plant yields increased for the hair-fertilized plants compared to the untreated controls overall, but were still lower than for the commercial, inorganic fertilizers in lettuce and wormwood, which are fast-growing plants. Yellow poppy, however, saw higher yields for the hair treatment. (The results didn't differ between fertilizers for the feverfew.)

Researchers suspect that some of the difference between hair and the inorganic fertilizers is due to the time it takes for hair to degrade and release its nutrients. So hair shouldn't be used as a sole fertilizer, at least for fast-growing plants, they concluded.

More research is still needed to see if human hair waste is a viable option for fertilizing edible crops though because of possible health concerns.

So, unless your hair is full of chemical dyes, i.e. coloring, keep that hair from your next hair cut and throw it in the garden.