The products at your local grocery store are deemed organic if they fulfill certain requirements, including no use of pesticides, chemical fertilizers, and herbicides. So how exactly can organic plants remain organic if we use something to get rid of pesky weeds? The answer is to, quite simply, use an organic herbicide.

You may not find an herbicide labeled “organic” in your nearest gardening depot, but you may see them eventually. Researchers at the National Institute of Health and Safety at Work in Rome and colleagues in the United States have begun investigating the inhibiting effects of aromatic oils when used on weeds. Their choice of aromatic oil was a mixture of phytochemicals derived from lavender, Lavandula officinalis.

Many herbicides already include plant essential oils, but the mixture of essential oils with the artificial chemicals has proven to be toxic, and sometimes carcinogenic. The use of an organic herbicide could not only be used on organic plants, but it could also be used in non-organic crops to help minimize toxicity. Although the use of lavender oils may be a bit more pricy, the health benefits would likely outweigh the cost.

The researchers tested the lavender oil on the weed Vicia faba. Not only was the lavender oil effective at killing the weeds, even at low concentrations, but the oil also affected the growth of soil microbes and fungi involved in crop growth. However, in order to prevent harmful effects on the crop itself, the researchers recommend that the oils should be applied either before planting or before seedling transplantation.

The oils also have a low environmental impact in the soil because the oils are easily degraded in by microbes and enzymes, compared to the high persistence and bioaccumulation of chemicals on soil.

Discussion Question: What disadvantages could you foresee in using lavender as a herbicide?

News Article: http://www.sciencedaily.com/releases/2009/05/090514083921.htm
Journal Abstract: http://www.inderscience.com/search/index.php