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Fun Fact Friday

Did you know that farmers have much trial and error when producing herbs intended for therapeutic value?

When farming medicinal plant material farmers are required to know a lot about these plants before they are able to grow them.  Most of us know that plants have varying chemical profiles depending on the weather, the soil and the regions in which they are grown.  In an area where there is more rain than a typical season, it will alter the profile from the oil yielded in a normal rain season.  One thing that I have found of interest is that time of day when plant material is picked can also make a difference.  You also want to make sure that the plants are harvested at the right time of year and age to produce the best chemical profile.

As I was looking into this I found more information on herbs than on essential oils specifically.  In North Carolina they have been trying to cultivate crops to increase the income for the farmers.  The problem is that many of the farmers have no idea what they are doing when it comes to growing medicinal herbs.  In 2004 they performed a 4-year study on several herbs. One of these studies concentrated on Goldenseal root.  During these studies they found that soil preparation was important. Goldenseal growth can be improved with an increase in the soil to a pH of 6.02 using lime, but the alkaloid content of Goldenseal was higher with the local natural pH value of 4.95. Finding a better yield and still keeping the medicinal value took some homework and in this particular study it was concluded a 5.8 pH was the best combination.  When conducting a similar study increasing the pH with calcium instead, it caused the goldenseal to decrease in yield and the alkaloid concentration did not respond to the calcium. 

Chris Burder owner of Stone Rise Farms, and an artisan Australian distiller kindly agreed to allow us to use his verbiage in this post. This is a some of what Chris has to say.

“Things which affect the end result of a steam distilled essential oil, in order of decreasing magnitude: Genetics, Harvest, Distillation, Epi-genetics and, least of all, Seasonal environmental variation within the same geographic location.

Genetics: the plants we use for oils have been around for hundreds or thousands of years in their current forms. Rosemary is a great example. Even though there are widely varying habits (short, spreading, tall) they all share the same wood, the same leaf form. Major changes in plant physiology take hundreds of years to effect, by natural means (seeding from natural cross-pollination etc). In the same way, each variation of rosemary that produces the different chemotypes will naturally take hundreds of years to effect any major change in oil composition. Any changes over a shorter period are very minor in comparison.

Harvest: the next largest way in which the oil composition can vary. For the flower-distilled oils (lavender for example), the bloom requires full development for the full suite of aromatic compounds to be in evidence. This is impossible on large scale mechanized farms because when most of the calyxes are full, too many are blown, and will be lost to the ground during harvest; therefore, slightly earlier harvest is needed for maximum recovery. The finest lavender oils come from hand-harvesting techniques because fully developed flowers are not lost. True Myrtle is another example of compound variation during harvest. Depending upon when harvest takes place, and therefore what plant parts exist (twig, leaf, berry, flower), while the compounds present are largely the same, the amounts of those compounds vary wildly. For example, if I have a Portuguese Myrtle, and I want to maximize the amount of myrtenyl acetate in the oil, I will harvest recently grown, mature leaves at the end of spring or beginning of summer, before flowering. On the other hand, to minimize myrtenyl acetate and maximize limonene+1,8-cineole, I’ll wait until mid-late summer.

Epi-genetics: the shorter-term genetic changes of plant physiology, over years or decades, mainly due to prolonged exposure of the non-indigenous species to its new environment, as opposed to if that same species continued its existence indigenously. Factors such as its new climactic conditions, its new soil composition etc. will eventually effect changes, some of which will be evidenced in the oil. These changes, in comparison with the previous two categories, are quite minor.

Seasonal environmental variation: unusually extreme conditions of heat, cold, rain, drought will have almost no effect upon the composition of the distilled oil. Where these factors become extremely important is that they are a major determinant of the YIELD of raw material at harvest. Quite simply, a plant under stress will consider its own survival to be of much more importance than procreation. For flower harvests, this means much less flower to harvest. For leaf harvests, the plant did not grow as much as it otherwise would have done in more ideal conditions and there is consequently less to harvest.”

When I think of this with oils and all the essential oils available on the market it really puts it into perspective about how much science, thought and preparation goes into making each and every bottle.  I hope this gives you all a greater respect for the process that goes into the development of your natural wellness products.

http://hortsci.ashspublications.org/content/47/8/976.full

Ruth Nelson