RO system

Discussion in 'Slipper Orchid Culture' started by practicallyostensible, Nov 13, 2007.

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  1. Dec 30, 2009 #21

    Shiva

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    I bought my RO system from a box store four years ago and installed it in my greenhouse. I had a problem at first with low pressure and got a booster pump. But once the water began to flow through the filters, the booster pump was not needed anymore. I bought extra filters but never had to change the ones that I got with the unit. The system is still working perfectly, though it takes about a whole day to fill half of my 35 gallons bin, which is fast enough for me. And I don't drink from the bin.
     
  2. Dec 31, 2009 #22

    Ray

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    Diane, if you use Dyna-Gro with RO, the pH of the resulting solution will be entirely too low for the well-being of your plants. That was something I "discovered" first hand when I got mine. However, correcting the pH is easy - I found that if I added Pro-teKt in the same volume as the fertilizer concentrate to the solution, it was fine.

    There are also pH-Up products available.
     
  3. Dec 31, 2009 #23

    etex

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    Thanks Ray!
     
  4. Dec 31, 2009 #24

    orcoholic

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    I got my RO system from Ray. Best prices and service is good too. Also, why support Lowe's or some other store that doesn't provide us with any good information. Since getting it installed in the fall, my plants have significantly improved. This is the first winter they have shown any decent growth.

    I use MSU/RO fertilizer at EC 0f 1.0. Ph is adjusted to about 6.2. The EC and Ph are very important because the orchids won't be able to properly absorb all the nutrients if they are too out of whack. TDS is not as reliable as EC unless you have carefully calibrated the meter and know the type of meter you have.
     
  5. Jan 1, 2010 #25

    Lanmark

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    What is EC and how is it measured? What chemicals do you use to adjust your ph up or down?

    ______________

    As for pure RO water diluting the nutrients from the cells of the plants, I would question that assumption. Plants get their minerals from many sources in nature. I am not a plant physiologist, but I know that the rain which falls from the sky and the dew which condenses on leaves are not chock full of minerals. Rain and condensed fog don't kill plants, including the epiphytic orchids which grow high up in trees in the cloud forests, so there must be some mechanism for the plants to hold onto the minerals they need, at least to some extent. There are many times I water my plants with pure RO water and they do not suffer from it. Of course I also use RO water with MSU/RO fertilizer added, but I give them a break from it from time to time.

    Human consumption of exclusively RO water isn't dangerous unless one's diet is devoid of minerals. Most of us nowadays get plenty of sodium, calcium, iron, magnesium, manganese, and so forth from the foods we eat. Mineralization cartridges are a gimmick to make money for the manufacturers and sellers of these devices. If anything, their primary purpose is to keep drinking water from tasting quite so flat.
     
  6. Jan 1, 2010 #26

    NYEric

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    You may be light in a few minerals but why not.
     
  7. Jan 1, 2010 #27

    Ray

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    EC is electrical conductivity, and there are very sensitive meters used to measure it, as we're talking something in the neighbor hood of 1 milliSiemen/cm.

    EC is a far more reliable measure of fertilizer concentration than is a measured TDS, as explained HERE.
    ________________________________

    The RO dilution of orchid "sap" is not an assumption. In discussion with plant physiologists from several universities I have learned that plants have three primary modes for the uptake of minerals:

    1) Active, to a limit - if the mineral is available, it will be taken up by the plant up until a certain internal concentration is reached. Calcium and boron fit into that category. (That is not to say they are the only ones, just the only examples I was given.)

    2) Active, with no limit - if it's available, the plant will take up as much as it can, socking it away in vacuoles in case of a future shortage. Phosphorus, even though a plant needs little, is apparently in this category.

    3) Totally passive - dependent upon concentration gradients, the plant either takes in or releases the mineral ions. This is where the continued use of pure water only for irrigation can be an issue.
     
  8. Jan 1, 2010 #28

    orcoholic

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    Lanmark,

    Ray explained EC. The MSU fertilizer comes with a spec sheet that tells how much fertilizer to add to RO water to get EC of 1. Incidentally, EC of 1.2 is good in the heavy growing months.

    I never had to adjust my Ph up. Before installing the RO system, I used citric acid to adjust Ph down. Now, with the RO and the MSU fertilizer, I don't need to adjust anything. My pure RO water is 7 and with the MSU it's around 6.2.

    I have heard, but never seen, that using straight RO water all the time can lead to plant nutrient deficiencies and the decline of the plants. I can't believe that drinking it will lead to any mineral deficiencies in humans. If anyone is worried about that, take a daily multivitamin with minerals. Probably a good idea anyway.
     
  9. Jan 1, 2010 #29

    Lanmark

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    Thanks for the info! :) Yeah, I wouldn't suggest using exclusively RO or distilled water all the time. I'm pretty sure it would lead to problems. In nature an orchid might get only pure rain water, but it also gets all sorts of plant and animal detritus along with a bevy of microorganisms to break down the detritus thereby releasing minerals for absorbtion. I purposely leach my plants of excessive salts and minerals from time to time by flushing the media and rinsing the leaves with distilled or RO water. I might do this two or three waterings/sprayings in a row before I return to using the MSU solution on a regular basis. I've never encountered any problems in doing this, and my plants look a lot nicer without all the buildup of salts. I guess I thought what was being suggested earlier in this thread was that any use whatsoever of RO or distilled water without added nutrients would damage a plant.
     
  10. Jan 1, 2010 #30

    cnycharles

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    Here is a link about long-term usage of low-tds water for animals (humans but tested on rats). It looks like long-term usage can leach things from the body, and that calcium and magnesium taken up through water can have more of an effect than other supplemented forms or in food. since water normally taken up into our bodies has some 'dirt' in it, the body doesn't have to use as many salts to move elements around. if the water is very clean, minerals and such that move elements around are in effect 'used up' unless alot more is taken in through food to replace it.

    http://www.who.int/water_sanitation_health/dwq/nutdemineralized.pdf

    very interesting are the health studies that show that people who move from harder water (with calcium and magnesium) to softer water will have increased chances of negative effects on the heart

    so, a little here and there is no big deal. all the time pure water doesn't look like a great idea, unless we're talking plants who specifically live in those environments where the water is very pure. remember that humans must always have salt in their diet at certain levels; I just read of bornean jungle people who are always trading with coastal people for salt to supplement their diet. of course westerners seem to usually have more than they need...

    direct observation of plants at work that were constantly misted or watered with very low tds water showed that nutrients were leached out of them, and tissue sample studies supported this observation. problem was resolved by always misting with 'seedling fertilizer' at low levels that had higher levels of calcium and magnesium than standard fertilizers. there were also pH problems that came about from using too much pure water on certain plants in soilless potting media, as the root exudates ended up changing the media pH (I think it was usually more a problem with pansies whose pH was heading too high when they preferred lower...)
     
  11. Jan 1, 2010 #31

    Lanmark

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    It won't download for me. It starts but then it stops. I went to the website and tried as well. :(

    I did see this one-sentence summary of the document in question there at the WHO website:

    "The expert meeting concluded that only a few minerals in natural waters had sufficient concentrations and distribution to expect that their consumption in drinking water might sometimes be a significant supplement to dietary intake in some populations."

    *** Hmmm. I was using Firefox but when I tried IE the document proceeded to download for me at once. :(

    Having read the article now, I'm glad I only use the RO water for making coffee and still consume the mineralized tap water whenever I want a plain old drink of water. I suppose it might still be a good idea to filter the drinking water with a carbon block type filter, especially since I use municipal "city water".
     
    Last edited: Jan 1, 2010
  12. Jan 1, 2010 #32

    Renegayde

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    4. CONCLUSIONS
    Drinking water should contain minimum levels of certain essential minerals
    (and other components such as carbonates). Unfortunately, over the two past
    decades, little research attention has been given to the beneficial or protective
    effects of drinking water substances. The main focus was on contaminants and
    their toxicological properties. Nevertheless, some studies have attempted to
    define the minimum content of essential elements or TDS in drinking water, and
    some countries have included requirements or guidelines for selected substances
    in their drinking water regulations. Although these are exceptional cases, the
    issue is relevant not only where drinking water is obtained by desalination (if
    not adequately re-mineralised) but also where home treatment or central water
    treatment reduces the content of important minerals and low-mineral bottled
    water is consumed.
    Although drinking water manufactured by desalination is stabilized with
    some minerals, this is usually not the case for water demineralised as a result of
    household treatment. Even when stablized, the final composition of some waters
    may not be adequate in terms of providing health benefits. Although desalinated
    waters are supplemented mainly with calcium (lime) or other carbonates, they
    may be deficient in magnesium and other microelements such as fluorides and
    potassium, as are most natural waters. Furthermore, the quantity of calcium that
    is supplemented is based on technical considerations (i.e., reducing the
    aggressiveness) rather than on health concerns. Possibly none of the commonly
    used ways of re-mineralization could be considered optimum, since the water
    does not contain all of its beneficial components. Current methods of
    stabilization are primarily intended to decrease the corrosive effects of
    demineralised water.
    Demineralised water that has not been remineralized , or low-mineral
    content water – in the light of the absence or substantial lack of essential
    minerals in it – is not considered ideal drinking water, and therefore, its regular
    consumption may not be providing adequate levels of some beneficial nutrients.
    This chapter provides a rationale for this conclusion.
    The evidence in terms of experimental effects and findings in human
    volunteers related to highly demineralised water is mostly found in older
    studies, some of which may not meet current methodological criteria. However,
    these findings and conclusions should not be dismissed. Some of these studies
    were unique, and the intervention studies, although undirected, would hardly be
    scientifically, financially, or ethically feasible to the same extent today. The
    methods, however, are not so questionable as to necessarily invalidate their
    results. The older animal and clinical studies on health risks from drinking
    demineralised or low-mineral water yielded consistent results both with each
    other and with more recent research, and recent research has tended to be
    supportive.
    Sufficient evidence is now available to confirm the health risk from drinking
    water deficient in calcium or magnesium. Many studies show that higher water
    magnesium is related to decreased risks for CVD and especially for sudden
    death from CVD. This relationship has been independently described in
    epidemiological studies with different study designs, performed in different
    areas (with different populations), and at different times. The consistent
    epidemiological observations are supported by the data from autopsy, clinical,
    and animal studies. Biological plausibility for a protective effect of magnesium
    is substantial, but the specificity is less evident due to the multifactorial
    aetiology of CVD. In addition to an increased risk of sudden death, it has been
    suggested that intake of water low in magnesium may be associated with a
    higher risk of motor neuronal disease, pregnancy disorders (so-called
    preeclampsia, and sudden death in infants) and some types of cancer. Recent
    studies suggest that the intake of soft water, i.e. water low in calcium, is
    associated with higher risk of fracture in children, certain neurodegenerative
    diseases, pre-term birth and low weight at birth and some types of cancer.
    Furthermore, the possible role of water calcium in the development of CVD
    cannot be excluded.
    International and national authorities responsible for drinking water quality
    should consider guidelines for desalination water treatment, specifying the
    minimum content of the relevant elements such as calcium and magnesium and
    TDS. If additional research is required to establish guidelines, these authorities
    should promote targeted research in this field to elaborate the health benefits. If
    guidelines are established for substances that should be in deminerialized water,
    authorities should ensure that the guidelines also apply to uses of certain home
    treatment devices and bottled waters.
     
  13. Jan 11, 2010 #33

    Lanmark

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    This set of questions is for Ray, orcoholic, Slipperfan or anyone else who may know the answers which will ease my tortured mind. :confused: :crazy:

    I still haven't found or figured out the most useful tidbits of information I had hoped to learn. Maybe I just overlooked them, so please forgive me if that is the case.

    Okay, so I have been digging through this site, through Ray's site, and I have read all that fertilizer stuff published by Bill Argo. I even read the labels which are stuck on the various packets of MSU RO granular fertilizer which I currently have around the house. Yes, I studied chemistry and physics and all those things, but it was a very long time ago for me. I do understand some basic concepts about the electrical conductivity of mineral salts dissolved in water and the variations in conductivity which can arise from the influences of all the possible variables. All of this stuff about PPM and TDS and EC starts out simple enough but quickly becomes very complex. It's all becoming a bit overwhelming and turning into a jumble in my brain. :sob:

    I want to use a continuous feed solution for my orchids using MSU RO formula fertilizer every single time I water. I would assume (but I could be wrong) this solution should be more dilute than if I were fertilizing my plants only once each week or once each two weeks or once per month. All of my plants are either mounted or growing in conditions quite equal to being mounted. They dry out quickly. As soon as they are dry, they get watered again. Excess watering solution runs off and is discarded.

    1) What would be the recommended PPM Nitrogen level and the recommended EC value for a constant-feed solution to be used for every watering on mounted mini vandaceous plants such as Neofinetia falcata which are growing in bright to very bright conditions?

    Would it be the 100 PPM Nitrogen you suggested on your website, Ray, or should I use something more or less? Is the 100 PPM of Nitrogen what you like to use in your semi-hydro pots, Ray?

    Would the desired EC value be the 1 to 1.2 EC values you previously stated, orcoholic, or are those the values you would use when fertilizing less often?


    2) Without having to purchase a second TDS meter and/or an EC meter along with Known-Value EC Testing Solutions and without having to engage in complex calculations, is there any way to determine the proper amount of MSU RO granular formula to mix with my RO water to achieve an acceptable approximation of the EC and Nitrogen PPM values which I am seeking to learn in question 1?

    Nowhere do I see anything that says "Add X-amount of granular MSU RO formula with X-amount of RO water to achieve X-value EC which is suitable for the constant-feed method of watering mini vandaceous orchids grown in good light." :rollhappy:

    I have found the following statements on two different MSU RO formula fertilizer labels in my possession:

    "100 PPM Nitrogen -- use 2/3 tsp or 2.8g per 1 gallon RO water"

    "125 PPM Nitrogen -- use 3/4 tsp per 1 gallon RO water"

    Nothing on either label says how to mix it in order to achieve any particular EC level. The label which gives the 125 PPM Nitrogen instructions recommends weekly use.

    My source tap water gives readings of 200 to 260 PPM TDS on my generic TDS meter. The levels tend to vary depending on the time of year, changes in water pressure and temperature and so forth. Readings have consistently been 213 PPM for the past couple of months. I produce RO water with readings which range from 4 to 18 ppm on my generic TDS meter. It never goes below 4 and slowly rises until I replace the membrane when it gets to 18. When I use my generic TDS meter in distilled water, I always get readings of 0 or 1 ppm.

    This morning when I mixed precisely 2.800 grams of MSU RO formula granular fertilizer (using a freshly calibrated digital scale) with precisely one gallon of my RO water which started out at a reading of 14 PPM TDS on my generic TDS meter, I ended up with a reading of 437 PPM TDS. Is this a suitable constant-feed solution to be used for everyday watering of my plants or is it too strong or too weak? Is there any way to make an educated guess as to what the EC of this solution I made would be?

    I am looking for guidance and suggestions. I understand there's no way you can give me exact numbers. Your educated guesses and approximations would be grand! :wink: Or am I asking too much? Do I still need to purchase a Known-Value Testing Solution, a second TDS meter and maybe even an EC meter and then calculate and chart out all of these numbers in order to know what to do? :eek:

    Ross over at the Orchid Board forum states:

    My mix of MSU is 3.5 cups powder to 1 gallon warmed RO water. I sit the bottle in a sink full of HOT water to assure the solution stays warm till all the salts dissolve. Then I use 1 tbsp (1/2 oz) per gallon RO water in final mix. Yields approx 125ppm Nitrogen solution. (Thanks Ray for the formula).

    I'd love to have a recipe such as that but one which is suitable for constant feed of my Neos. :)
     
  14. Jan 11, 2010 #34

    SlipperFan

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    Way over my head, Mark! Too much for my little artist brain.
     
  15. Jan 11, 2010 #35

    cnycharles

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    one thing to consider is that when your mounts (or the pellets in s/h culture) dry, the fertilizer concentration will rise. so, that last drop of water on your neo's roots will be very concentrated because the salts will 'move' towards the water. if you are watering them every day, then maybe even lower fertilizer rates would be helpful for them. what you are going to put in a pot in s/h culture (weekly watering) would be higher because those pots are pretty much 'always' wet though if you go longer they will 'dry' a bit and the fertilizer would be concentrated. so, maybe using lower rates would be helpful.

    I don't know if this is a good way to think or not, but if you were trying to translate how much fertilizer you would use in a gallon of water when irrigating once a week down to more frequent waterings (say seven times a week) then divide the weekly fertilizer amount by 7, and put that in your gallon of water. I don't know if this would be too low, but maybe a good target to start at and work upwards from.

    There is a quick and dirty way to figure out what ec your fertilizer water is likely to be.... start out by measuring your tap water (or whatever source water) to get it's ec. Mix into the water the amount of fertilizer the bag says will get it to 100 ppm's; measure that ec. take the second ec reading and subtract the ec of the starting water. the amount of fertilizer you added changed the ec reading by x amount. half the fertilizer would yield half the raise in ec - reduce or raise your fertilizer amount until it matches the ec you want in your final irrigation solution. if the amounts on the bag are too much for your final desired ec, then add a teaspoon to your water, measure and go from there (this is if you have a meter graded for ec).

    barring all of that, you can visit this page http://www.firstrays.com/tds_and_ec.htm and since tds, ppm's and ec are basically connected (though not always exactly the same), this should explain it. once you figure out that 'this ppm' equals 'this ec' for a few different rates, then you don't have to figure out both; just use your ppm or tds meter. I think you might be trying to figure too much. ...reading into your post again, I noticed that you asked if 400 and something tds of fertilizer water might be too strong or weak for mounted orchids, I would say that it was too strong. I think 400+ tds (figuring that your tap water was basically 0) is the rate of fertilizer that would normally be used for vigorous, quickly growing chrysanthemums which are feed hogs. if I have my values switched around (tds, ec ppm) please let me know

    I have to add that I think you may be making this way too complicated and worrying about numbers too much... 100ppm of fertilizer is a very low rate and used for seedlings that can be easily burned by excess fertilizer. very heavy feeding plants would have 400 and up ppm's. There really isn't a need to figure out e.c.'s. If you have an ec meter you can measure what ends up after you mix up what the bag says is 100ppm's of fertilizer. if you have a tds meter, measure what the end result is from what that bag says is 100ppms after mixing in the fertilizer. having a different number from a different scale in my opinion is just converting from celsius to fahrenheit
     
  16. Jan 12, 2010 #36

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    *Hugs* @ Dot. Ha ha :rollhappy: it's not too complicated for you. The package of MSU RO formula fertilizer I have which recommends mixing it at 125 PPM Nitrogen (3/4 tsp per gallon, using once per week) came from Porters. :p You probably made the label. :poke:

    Thanks Charles. I sincerely appreciate your input! :) I see what you are saying about the drying of the mounted orchids between waterings causing the salts to increase in concentration and create the risk of burn. I'm really glad you mentioned that. I needed to be reminded of that aspect of it. Indeed my intention has always been to use something like 1/4 strength fertilizer for my mounted plants, but I've noticed that the recommended mixing strengths for the MSU RO formula varies quite a bit depending on who I buy it from. I imagine this could be because different growers may fertilize at different frequencies and they also grow different types of orchids. Their recommendations are based upon their own experiences.

    No one has ever told me the strength at which I should be mixing my MSU RO formula fertilizer for use on Neofinetia falcata, whether for once a month feeding, once a week, or daily. That is part of the reason I am asking these questions.

    I don't know what constitutes "full strength" MSU Fertilizer so that I can dilute it to quarter strength or less for daily use. :p

    Charles, you said 100 PPM is considered a low strength fertilizer safe even for seedlings. Are you talking about 100 PPM of Nitrogen or 100 PPM total dissolved salts?

    Charles, I used exactly what the MSU RO formula package said to use in order to achieve 100 PPM of Nitrogen and it yielded a total of 437 PPM TDS. Subtract out the 14 PPM I started with and obviously I have added a total of 423 PPM. If 100 PPM of that is Nitrogen, I can only assume the remaining 323 PPM are all the other nutrients and minerals which are included in the MSU RO formula.

    I already visited that page you referred to at Ray's about TDS before I made my last post, and I can't find anywhere on that page which says a certain number of PPM equals a certain level of EC. It says right there on that page that when Ray has achieved the target of 100 to 125 PPM of Nitrogen, his TDS are measuring between 380 and 475 ppm on the one TDS meter of his and they are measuring between 470 to 590 on the other TDS meter he has. It sounds to me like my numbers might be right on target, but I still don't know if that is considered to be full strength or diluted.

    I had never even thought about using EC as a measure of the strength of my fertilizer or quality of my water until Ray and orcoholic brought it up earlier in this thread saying how important it was and how it was so much more accurate of a measure than TDS. It made me worry that the strength of my fertilizer solution might be too weak and actually leaching nutrients out of my plants.

    As for me making it more complicated than necessary, lol, I didn't. Perhaps my wording has made it more complicated, but everything I have written is only based upon the numbers being thrown around by First Ray's website and orcoholic. I'm just trying to crunch the numbers and determine what their recommendations would be for my particular species and situation.

    Stupid me, I'm just trying to get some simple formula I can use for good results, and in making my explanation, I turned it all into a big octopus. :crazy:
    :eek::eek::eek::eek: :( :eek::eek::eek::eek:
     
  17. Jan 12, 2010 #37

    cnycharles

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    Hello again,
    When you read a chart that tells you that a fertilizer mix will result in 100 ppm or whatever, usually it's talking about the amount of N in the mix. Since the fertilizer has more than N in it, your total tds/ppm will be higher. EC may be more exact than the total tds of a solution, but it's more of a tolerance feature I would say, maybe like the difference between a reading from a publicly-owned gps reader and a military one; public ones have a slight error built-in to prevent use for something like missle tracking to targets, and the military ones don't have the 'inexact gene' built in. The job gets done and most everyone is happy, and after a long distance you would likely see a difference but for fertilizing plants you really aren't going to see that much difference. Your EC might be slightly more or less than a TDS reading, but again in my opinion you might just as well not worry about it, unless you want to buy an EC meter and measure everything that way. I don't think any company is going to list what the final EC will be of a fertilizer mix because it will change depending on the water it's going into.

    Also, there isn't any official 'full-strength' amount of any particular fertilizer, it's all subjective depending on what types of plants you are growing, when you want it to be a certain size,the environmental conditions, the frequency of watering and all of that. Remember, Andy of Andy's Orchids feeds his orchids by grabbing whatever bag of whatever fertilizer is closest at hand. The numbers you point out Ray had from two meters which was in the upper 400's is considered quite a high rate of fertilizer. When I mention a low rate of fertilizer ppm's that is adequate for seedlings, it's just a number off the top of my head. If you have not high tds tap water, a rate of 100 to 150 ppm's of nitrogen as listed on the bag is a normal general seedling rate. Someone else who wants a different growth rate and all may use something slightly higher. If your water has very high tds without fertilizer in it, then to get a low rate of total tds but still have weak fertilizer (seedling or everyday feeding rates), you might need remediation to have a lower starting tds for your water. If you are adding fertilizer to water, I'm pretty sure that nutrients aren't going to get leached from your plants. If you have very low EC water to start with and you just water, you might have that happen, but if you have normal tds tap water then adding fertilizer to it will prevent any leaching. Maybe you can ask around to people who are also growing neofinetias mounted or otherwise, and ask what rates work for them along with their watering frequency and all that. I would start using something fairly low and use it for awhile while you are asking around, and see if things look like they are growing fine or don't look so hot. If they are struggling after a while, try a little more. Fertilizing is not exact unless you have had a university test growing a certain cultivar of plant for a few generations (of plants) under controlled conditions with controlled types and quantities of plant food. After that they can give fairly accurate ideas about what to do under what conditions. Since this hasn't happened with too many orchids (except some phals and others grown for pot plants) then it's more of a guessing game. At work we have pretty good guidelines for what types and amounts of fertilizer work for certain plants, but then this is still a guideline and depends on how fast or slow you want your plants to grow, and what temperatures and all that the plants are exposed to.
     
  18. Jan 12, 2010 #38

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    Right. That is exactly what I am saying and that is exactly what I did. I made the solution to achieve 100 PPM of Nitrogen per the instructions on the container and it resulted in the TDS value of 437 PPM. Part of that number was the 14 PPM I started with in my own water before adding any fertilizer. 323 PPM of that is the other components of the fertilzer mix, and 100 PPM of that is the Nitrogen.

    Is it? But Why? Those are the TDS numbers he achieved after he added the amount of fertilizer required to his purified water in order to achieve the 100 PPM level of Nitrogen. It's the same thing I did. Nitrogen does not come alone. It comes with all the other ingredients too. Mix to get 100 PPM Nitrogen and you get a lot of other stuff too.

    I have low TDS to start with: 14 PPM. I added 2.8 grams of fertilizer per the instructions on the MSU RO formula fertlizer bag to one gallon of water in order to achieve that 100 PPM of Nitrogen which you say is a normal general seedling rate. My resulting Nitrogen PPM of 100 came along with an additional 323 PPM of other stuff. Add in the 14 PPM starting number from my water and the TDS value becomes 437. So how is this considered a normal general seedling rate yet you consider Rays's TDS numbers in the 400s as being high? His TDS numbers in the 400s and mine are both the result of mixing RO water with enough fertilizer to achieve 100 PPM Nitrogen.

    Something's not adding up here. :wink: You must be referring to 100-150 PPM TDS as being a normal strength for use on seedlings, not 100 PPM of Nitrogen which has a much higher overall TDS value.
    _____________________________________________

    I've been growing Neofinetia falcata for years. I have great success with them. I simply wanted to know if there was something I was doing wrong or if there was something I could be doing better. I was introduced here in this thread to the idea that measuring Electrical Conductivity directly was a much better idea than just using a measuring spoon or attempting to interpret the Total Dissolved Solids number. I wanted to understand this new and improved way of doing things. Unfortunately, I still don't. I guess I should just shut up and buy the testing solutions and and the EC meter and figure it out for myself. :rollhappy:

    There was talk here of RO water being bad for plants and so forth. It made me wonder if I was using it on my plants too often. I also thought, what should I do if I fertilize a plant using a stronger solution but only do it once every two to four weeks? What then should I use to water and mist this plant with in the interim? All these years everyone has said over and over how terrible it is to use tap water on orchid plants. But here now they are saying how pure water will damage a plant too, so I thought what should I do? I can't use tap water, I can't use pure water, and I'm equally certain I can't just use full strength fertilizer every time I water a plant without frying it to death. :rollhappy: And now you are saying there is no such thing as "full strength fertilizer" :poke: Should I dilute it? But wait, how do I dilute it if I don't know what full strength is? :p

    Normally I water every time using RO or Distilled water mixed with MSU Fertilizer RO formula to get a value of about 31 PPM Nitrogen and a TDS value of about 109. I give my plants a break from fertilizer one day out of every week on average by thoroughly flushing them with plain RO or Distilled water. I think I'll just stop worrying about it and do what I have been doing all along for the past decade + :) I have no idea if the fertilizer regimen I am using is too weak or too strong, but my plants grow and bloom. I think there's always room for improvement and it's always good to learn more, but I can see this is getting to be a nonproductive effort on my part and I'm probably just annoying everyone in the process. :evil: Sorry to trouble you all with my questions. I'll just drop it. :eek: :sob:
     
  19. Jan 12, 2010 #39

    Ray

    Ray

    Ray

    Orchid Iconoclast

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    Damn! I wish I had not been away - I might not have had to read all of this!!!

    • I believe the reason nurserymen use nitrogen loading as the control is fairly simple:
      1. Nitrogen is the single, largest mineral used by a plant, i.e., the "most important" one.
      2. As the levels of the other mineral ions will (optimally) change based upon the types of plants grown, it's easier to focus on ppm N, when using a specific formula.

      Poinsettia growers have clearly established that it takes 1/2 gram of nitrogen to get a plant from cutting to full bloom (full bract?). By taking into account the pot size, volume of medium, absorption capacity of the medium, and time until harvest, they can adjust their watering frequency and fertilizer concentration to provide that - no more and no less.

      Orchid-growing is far more diverse, both in terms of needs of the genera and species, types of culture, and cultural conditions, that we cannot possibly be that focused, relegating us to the "let's approximate" technique.​
    • 100-150 ppm N was Bill Argo's recommendation for use at every watering for a mixed collection of plants grown at MSU. The implications of that include:
      1. At that concentration, some plants might be getting too much, others might be getting too little.
      2. If you grow under higher-PAR conditions, you might want to bump that up a bit, to go along with the higher growth rate.

      My own experience in a greenhouse in southeastern PA (no supplemental light, but RH is maintained in the 60%-70% range), growing stuff mounted, in baskets, s/h culture, and "normal culture" using LECA and bark-based mixes, with genera ranging from catts, encyclias, cymbidiums, paphs, phrags, phals, neofinetias, ondiums and their various intergeneric hybrids, botanicals like cochleantes, bollea, pescatorea and the like, oddball species, vandas, and zygopetalums, is that 125 ppm N for all at every watering seems to be just fine - even with the potential for concentration upon drying Charles mentioned.​
    • The labels I put on the Greencare MSU jars I repackage does not have the EC info on it primarily because folks don't usually use it, and I didn't have space! I have, however, retyped the info on the label as it comes from Greencare:
     
  20. Jan 12, 2010 #40

    etex

    etex

    etex

    Guest

    I just got my MSU Pure Water Special by Green Care and the label says 1 tsp per gallon, so I would assume this was full strength. Will use a little less for babies. Would adding Protekt still be useful?
    Can not see a problem drinking RO water. It is better than the crap we have out here in the country. The bottled drinking water we have also uses RO, in addition to Carbon filtration,Ultra filtration,Submicron filtration,Ozonation and ultraviolet light.
    Low Magnesium can cause torsades de pointes, a very nasty ventricular arrhythmia that is quite scary to see, but is easily treated with IV Magnesium. Many Cardiac patients are on potent diuretics that pull minerals from their bodies.Have worked as a Cardiac Nurse for several years and no one ever pointed to RO water as a cause of CV disease. Besides, we get our minerals from other sources.
     
    Last edited by a moderator: Jan 12, 2010

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