This article is really a shameless repost from a journal entry from 2007. However, since the question is raised often, it has been placed here as a permanent article.
We got a question this week about growing (and selling) produce that
is legally allowed to be called "organic". For those of you who aren't
familiar with it, "organic" is a legal term when it involved food
labeling. You must meet a rather intensive list of requirements in
order to legally sell a product as "organic". The US Department of
Agriculture has specific requirements and guidelines that must be met
(and certified) before products can legally be called "organic".
If you're thinking about growing organic fruits and vegetables hydroponically, you'll probably want to know about OMRI.
OMRI is the Organic Materials Review Institute. It's a non-profit
certifying body for "input products" used in certified organic
production. In simple terms, they pre-approve fertilizers and
additives, so you can save yourself a lot of headaches when you go to
market.
You're probably thinking to yourself, "I use a really good nutrient mix. It's got to be organic." However, this is often not the case. The vast majority of hydroponic nutrients are actually not OMRI listed. In the hopes of offering assistance, I did some research on the more common nutrients and supplements on market.
American
Agritech / Botanicare: No products are OMRI listed. I researched the
Pure Blend Pro line, Liquid Karma, Sweet, and Cal-Mag. This doesn't
mean that their nutrients aren't good. In fact, I like them quite a
lot. From my research, I found out that a single-step in their
production process is "uncertifiable". If one link in the chain is
broken, a product cannot be certified.- General Hydroponics: No
products are OMRI listed. I researched the FloraNova line and
FloraBlend (my favorite compost tea). It appears that part of the
"refining" process used by General Hydroponics makes their products
ineligible for OMRI listing. Hydroponic nutrients need to stay "in
solution" in order to be of much use to the plants. If all the "good
stuff" falls to the bottom of the reservoir, it can't help the plants.
Although I don't know the specifics of their manufacturing process, it
appears that their methods of keeping nutrients in suspension break the
"certification chain". This is not a criticism. I'd rather have a
good non-listed nutrient, than a lousy listed one.
- Technaflora: Some of Technaflora's products are OMRI listed. It's not the whole line, but Technaflora is the only one of the major manufacturers to have anything that's listed. Technaflora has Thrive Alive B-1, B Seaweed, and Soluble Seaweed
listed with OMRI. When I spoke with a Technaflora representative, they
gave similar reasons for why the whole line isn't approved.
Apparently, the requirements of hydroponic gardening make OMRI listing
a pretty difficult goal. I was pleased to see the listing. I'd say,
of all the nutrients that I use, Technaflora is the best at "staying in
suspension". They tend to "fall out" less than most other nutrients.
- Grotek: Only one product produced by Grotek is OMRI listed, their commercial Fishplus fertilizer.
I'll admit that I've never had experience with Fishplus, so I can't
offer much of a comment. However, Grotek's regular like is
"organic-based". "Organic-based" is a good thing, just not legally
"organic". Although I don't have any proof, I suspect that Grotek has
the same trouble obtaining an certifiable suspension as the other
manufacturers.
- Earth Juice: The entire Earth Juice line is OMRI listed.
I can't say much about Earth Juice, as I've never used anything they
make. However, if you're trying to grow an organic-certifiable crop,
they appear to be your first (and only) choice, short of mixing your
own nutrients from scratch.
- House & Garden (Van de Zwaan): Sadly, H&G has no product that are OMRI listed.
I'd
expect that we'll start to see more nutrients that have OMRI listing in
the coming years. At this time, it appears that most manufacturers
have opted to produce a product with superior operating properties, at
the cost of certification. The manufacturers put a lot of effort into not clogging our sprayers, more than is usually visible to the amateur grower.