Aeroponic Herb Production
Answered by: Conrad Richter
Question from: John Lunghusen
Posted on: November 25, 1998

I am interested in the commercial growing of pharmaceutical herbs in a organic aeroponic system (using worm juice). I have started with Valeriana officinalis which is growing well. What other crops can you suggest for a environmental controlled glass house? Preferable high value crops, Ginseng and Hydrastis have been suggested as the highest value, but would they be suited to such a system.

The economics of producing medicinal herbs in controlled environments is controversal. There seems to be little doubt that many medicinal plants can be grown successfully this way, but at what cost, and fetching what price. The capital cost of the equipment and buildings, plus the costs of energy, fertilizer, pest controls and labour are difficult to recoup when competing against field produced herbs.

There are several important advantages of growing in controlled environments. Whether these advantages outweigh the higher input costs will depend on each crop.

Some advantages:

1. Faster production cycle. Anecdotal reports suggest that Echinacea can be grown to maturity in a as few as nine months when in the field it takes three years. We have yet to see studies that prove this, and show that the resulting product is comparable to the field product. Meeting the active constituents standards of the market is very critical for most herbs, and we have little information what accelerated growing does to constituent levels.

2. Cleaner product. Good Manufacturing Practices standards have been, or are being, introduced in many countries. Manufacturers will require cleaner product that is generally free of soil, sand, and debris to meet GMP standards.

3. Consistent product. There is ample evidence to suggest that environmental conditions have a huge effect on the active constituent levels. Our own research showed that germplasm exhibiting high actives levels in one year can drop precipituously the next year. There are several possible causes for the drop, but environmental conditions are definitely one of the reasons. Manufacturers are demanding a better defined, more consistent product year after year, and production in a controlled environment production may be necessary to deliver that consistency.

Assuming that the economics of the concept make sense, there are many herbs that could be considered. It is important to realize that high value by weight is not necessarily a good indicator of which herbs are worth trying. Ginseng prices are above average but the cost of production and the length of the production cycle is four years and the risk of loss to disease is high. Gotu kola which commands much less per kilogram than ginseng yields a harvest in a little as 3-4 months and suffers far fewer problems from pests and diseases.

Because of ginseng’s susceptibility to disease it seems unlikely that controlled environment production would work well. Ginseng cannot tolerate heat (above 25 degrees Celsius) for long because disease sets in, which would necessitate expensive cooling. Goldenseal (Hydrastis) requires much the same conditions as ginseng, but we would expect that it would have fewer problems with disease. It requires 2-3 years in the field; but how long it would take in greenhouses is unknown. Again, no one has proved that it can be grown at a profit inside greenhouses.

Echinacea has been touted as a good candidate crop for greenhouse production. At least one grower in Canada claims to be growing Echinacea successfully this way, but he has not revealed details of his system or his production numbers and costs.

According to Gordon Creaser, a consultant on hydroponic herb production, a number of operations in Canada and the U.S. are trying to grow medicinal herbs. St. Johnswort, valerian, and feverfew are some that are being tried.

Dr. M. Mirza of the Alberta government’s research group on herbs is the leading researcher on greenhouse production of medicinal herbs in Canada. He has been presenting his preliminary results at conferences in recent years, but we are not aware of any publications of his work on greenhouse and hydroponic herbs published to date.

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