Best liquid organic fertilizer

[Orchid Whisperer]

Originally Posted by mexorchid

What an interesting thread and much to learn from it in different issues

I am not at all an experienced orchid grower, all my previous orchids have been "in the wild" only, so I can't give an opinion about fertilizing. But I would like to comment on the word "organic":

It means by definition that something is grown in a "natural way": no sewedge sludge or chemical pest control, no genetical engineering, no synthetic fertilizers used; for plants they have to be grown in soil that has not been treated with any of these for 7 years (that's in my country, laws may vary). For animals and their products: their food has to be organic, they need access to outdoors, no antibiotics,…

That means that a fertilizer is not organic because it uses chicken droppings. It's organic only if the chicken and its food are grown according to organic standards.

As for an element in a fertilizer: if you extract a certain element from something organically grown, chemically it is in no way different than an element produced in a lab.

In Canada "Le Paradis des Orchidees" in Montreal is producing their own organic fertilizer. How organic it really is - no idea

I understand that the word "organic" is used in the way that you state (e.g., organic farming), but that is really not what organic means from a scientific standpoint (of, pertaining to, or derived from living organisms; or, referring to the chemistry of carbon-containing compounds).

Sewage sludge? Yes, it's an organic material. I occasionally use a sterilized sludge product (Milorganite) on my orchids outdoors in the spring, BTW.

Genetically modified? They are still organisms, so they are organic. [Edit: Forgot to mention that "genetically modified" or "genetic engineering" are very broad terms; my dachshund is the product of centuries of genetic engineering; my hybrid Cattlianthe Golden Wax is also genetically engineered]

Chicken litter? Organic, regardless of what is fed to the birds.

Chemical pest control? I have seen rotenone, pyrethrins, neem oil, Bordeaux mix, etc. offered as "organic" pest & disease controls. They are all chemicals. Interestingly, the Bordeaux mix is copper sulfate (produced industrially from copper metal treated with sufuric acid) mixed with slaked lime; nothing organic in there! All of these can be used properly, or misused (rotenone is a powerful fish toxin, for example).

There is absolutely zero difference between nitrate nitrogen derived from a "synthetic" source and nitrate-nitrogen derived from an "organic" source. Similarly, ammonia from an "organic" chicken litter source is neither less nor more toxic than ammonia from chicken litter that is considered "non-organic". Ditto phosphorus, potassium, as well as all the various micronutrients.

So, "organic" in the organic farming or gardening sense, really refers to a set of practices that some people feel better about, for a variety of reasons. I have both a 1946 edition of Websters New International Dictionary and a newer American Heritage dictionary on my bookshelf. The 1946 edition contains nothing that hints at the "organic farming" version of "organic", while the new version does refer to it.

[RandomGemini]

RO water still contains chlorine if the system does not include a carbon/charcoal stage of filtration. RO membranes by themselves, do not remove chlorine. Water run through a brita pitcher is dechlorinated. However, many municipalities have switched from using chlorine, to chloramine. Standard carbon filters are not enough to remove chloramine from the tap water and a fair amount of cloramine will remain behind after going through the RO process, unless you have a carbon filter that uses catalytic carbon.

[Ray]

I have never seen an RO system that did not have carbon filtration - although I suppose they might exist.

All filtration, including RO, is statistical - they remove "X"% of what's going into them. If all contaminants were spherical, then one could - depending upon the design - guarantee that nothing above a certain size will get through, but in reality dissolved or suspended stuff is not the same dimension in all aspects - a 1" grid would stop 100% of all sewing needles if they all tried to pass sideways.

So basically, the purer the input water, the purer the output water, but depending upon the particular dissolve species, the relative ratios may change, as well.

Let's assume a water supply has equal conentrations of two dissolved ions - "little" and "big". The RO system may take 99% of "big" out and 93% of "little" out, so has a rated efficiency of 96% dissolved solids removal.

Here's a chart of the relative sizes of dissolved and suspended species. Note the stuff above the blue "RO" bar at the bottom - it can still pass, but will do so in very small percentages.

[RandomGemini]

Most folks I know with RO/DI units don't change the cartridges in them often enough, and carbon loses its efficacy in a short amount of time because it's porous and the pores in it become clogged. Carbon cartridges should be replaced every 3-6 months (3 months if you are running the unit constantly), otherwise they're not filtering much of anything for you.

My RO/DI unit allows you to pick and choose the cartridges and a lot of the aquarists I knew, didn't bother with the carbon filter because they had to be replaced frequently and they ran carbon in their aquariums anyway. That's why I mentioned it.

[mexorchid]

Originally Posted by Orchid Whisperer

I understand that the word "organic" is used in the way that you state (e.g., organic farming), but that is really not what organic means from a scientific standpoint (of, pertaining to, or derived from living organisms; or, referring to the chemistry of carbon-containing compounds).

Sewage sludge? Yes, it's an organic material. I occasionally use a sterilized sludge product (Milorganite) on my orchids outdoors in the spring, BTW...
Chicken litter? Organic, regardless of what is fed to the birds......

Sure in chemistry there is organic matter (is that the correct term in english?) containing C and inorganic ones without. I just thought the discussion was more from a consumer point of view and by law a product can only be defined as "organic" if it follows certain criteria.
Sorry, I didn't want to offend the chicken! or give an opinion on how good a fertilizer or sewage sludge is and as I said: an element won in nature is in no way different from an element produced in a lab. But I'm not a chemist so it didn't occur to me to understand "organic" as in organic compound - my mistake, sorry.

[DavidCampen]

The commonly used RO membranes are damaged by exposure to the chlorine in tap water.

Reverse Osmosis Membrane Sizing & Upgrade
"TFC Membranes cannot tolerate chlorine. TFC Membranes are more efficient and are the standard type used in today's RO Systems"

http://msdssearch.dow.com/PublishedL...romPage=GetDoc
When FILMTEC FT30 membrane is used in the reverse osmosis process, the RO feed must be dechlorinated toprevent oxidation of the membrane. FT30 membrane has some chlorine tolerance before noticeable loss of salt
rejection is observed. Eventual degradation may occur after approximately 200-1,000 hours of exposure to one
mg/l of free chlorine (200-1,000 ppm-h tolerance). ... By comparison, some other polyamide RO membranes have essentially zero chlorine tolerance. The superior chlorine tolerance of the FT30 membrane can be attributed to the thicker barrier layer (about 2,000 Angstrom) and the fact that the polyamide is crosslinked "

I use carbon cartridges to remove chlorine before the water goes to the RO membrane.

[ALToronto]

Originally Posted by DavidCampen

The commonly used RO membranes are damaged by exposure to the chlorine in tap water.

Reverse Osmosis Membrane Sizing & Upgrade
"TFC Membranes cannot tolerate chlorine. TFC Membranes are more efficient and are the standard type used in today's RO Systems"

http://msdssearch.dow.com/PublishedL...romPage=GetDoc
When FILMTEC FT30 membrane is used in the reverse osmosis process, the RO feed must be dechlorinated toprevent oxidation of the membrane. FT30 membrane has some chlorine tolerance before noticeable loss of salt
rejection is observed. Eventual degradation may occur after approximately 200-1,000 hours of exposure to one
mg/l of free chlorine (200-1,000 ppm-h tolerance). ... By comparison, some other polyamide RO membranes have essentially zero chlorine tolerance. The superior chlorine tolerance of the FT30 membrane can be attributed to the thicker barrier layer (about 2,000 Angstrom) and the fact that the polyamide is crosslinked "

I use carbon cartridges to remove chlorine before the water goes to the RO membrane.

I have a 5-stage RO system. Would it have a carbon pre-filter?

[DavidCampen]

Originally Posted by ALToronto

I have a 5-stage RO system. Would it have a carbon pre-filter?

With all those stages I would certainly hope so but I am not very familiar with home systems.

I built my own RO unit. I have a particulate filter then carbon filter then RO membrane. Actually, I have 2 carbon filters with the ability to sample the water between the 2 filters so that I can see when chlorine breaks through the 1st carbon filter.

[naoki]

So David, is water out of water softener cause the same problem to RO membrane? Cl is there whether it uses KCl or NaCl as the softener salt. TDS of my well is >800ppm, so the softened water contains fair amount of Cl.

[DavidCampen]

Chloride does not hurt RO membranes, it is the chemically reactive, elemental chlorine that damages the membrane. Water that has gone through a softener is good for the membrane because the NaCl or KCl will not precipitate out onto the membrane like the minerals that cause hardness do. I would think that the 10 to 20 ppm of NaCl that would remain in RO treated softened water would not hurt plants.

If I were using softened water from input water at 800 ppm I would a KCl softener instead of NaCl.