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Thread: PH info and problem solving.

  1. #51

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    I have no idea of the importance of EC,So when I came across this it started to explain some of the question I might later ask,Maybe as CW says,This info maybe out dated and so would not state what is written as fact,More of a guide, Hope it helps some that are now questioning whet ec has to do with all this.

    The why and how to testing the Electrical Conductivity of Soils.

    Electrical Conductivity is a very quick, simple and inexpensive method that home gardeners can use to check the health of their soils. Whereas pH is a good indicator of the balance of available nutrients in your soil, Electrical Conductivity can almost be viewed as the quantity of available nutrients in your soil. (NOTE: Only nutrients that are dissolved in the soil water is “Available” for crops to take in).

    What is Electrical Conductivity?

    In the soil, the Electrical Conductivity (EC) reading shows the level of ability the soil water has to carry an electrical current. The EC levels of the soil water is a good indication of the amount of nutrients available for your crops to absorb.

    Think of it like this, all the major and minor nutrients important for plant growth take the form of either Cations (positively charged ions) or Anions (negatively charged ions). These ions that are dissolved in the soil water carry electrical charge and thus determine the EC level of your soil and how many nutrients are available for your crops to take in. Knowing your soils EC can allow you to make more educated farming decisions.

    To support these claims, Researchers at Clemson University documented the correlations between EC and different crop inputs, documenting these at multiple sites over multiple years. They found unmistakable evidence showing that yield data have consistently supported the EC correlations with water, fertilizer, and pesticide use.

    Using EC data to develop zones, in six on-farm tests, they overlaid yield maps developed after the crops had been harvested over EC maps developed before the crops were planted and found that the two maps match perfectly.

    They also found that where EC levels were high (More available nutrients) less fertilizer is needed but more weed control in places where they had a morning glory problem. For example on sandier soils with low EC ratings, it took only a quarter-pound of active ingredient in the herbicide to get 80 percent control morning glory. On heavier soils with higher EC ratings, it took up to five times that amount to achieve the same level of control.

    Other factors also contribute to soil EC variability include the connectivity of the soil water through soil density, soil structure, water potential, precipitation, timing of measurement, soil aggregation, electrolytes in soil water (e.g. salinity, exchangeable ions, soil water content, soil temperature). Also the conductivity of the mineral phase affects the EC reading for example the types and quantity of minerals, degree of isomorphic substitution, and exchangeable ions. Regardless of what these multiple causes of EC variability are, what still remains is that EC measurements are consistently correlated to soil properties that affect crop productivity, including soil texture, Cation Exchange Capacity (CEC), drainage conditions, organic matter level and salinity, so knowing your soils EC level is a great predictor of your plants health.

    For example if the soil EC is too high, it can be indicative of excess nitrogen based fertilizer or a high level of exchangeable sodium. Soils with an accumulation of exchangeable sodium are often characterized by poor tilth and low permeability making them unfavorable for plant growth. Soil EC is also related to specific soil properties that affect crop yield, such as topsoil depth, pH, salt concentrations and water-holding capacity. Thus EC is a great tool for explaining what your yields could be and taking action to get better yields.

    Testing the EC of your soils
    The way that Electrical conductivity can be measured is using an EC meter. The probe or sensor consists of two metal electrodes and a constant voltage is applied across the electrodes resulting in an electrical current flowing through the sample. Since the current flowing through the water is proportional to the concentration of dissolved ions in the water, the electrical conductivity can be measured. The higher the dissolved salt/ion concentration, the more conductive the sample and hence the higher the conductivity reading.

    The unit of measurement for Electrical Conductivity is microSiemens per centimeter (µS/cm). Up until about the late 1970's the units of EC were micromhos per centimeter (µmhos/cm) after which they were changed to microSiemens/cm (1µS/cm = 1 µmho/cm). Also a 1000 microsiemans is equal to 1 millisieman (1MS/cm)

    Interestingly, the unit "mhos" derives from the standard name for electrical resistance reflecting the inverse relationship between resistance and conductivity - the higher the resistance of the water, the lower its conductivity. This also follows from Ohm’s Law, V = I x R where R is the resistance of the centimeter of water. Since the electrical current flow (I) increases with increasing temperature, the EC values are automatically corrected to a standard value of 25°C and the values are then technically referred to as specific electrical conductivity. A good EC meter will have ATC (automatic temperature compensation) so you can get accurate results regardless of sample temperature.

    To get a soil extract we recommend a similar method as we do for testing pH so that both EC and pH measurements can be taken at the same time.

    •Gather a fresh soil sample in a plastic zip-loc bag. Try to get a profile from the top 6” of soil that the plants will grow in and take care not to contaminate the sample by touching with anything.
    •Open the bag and let it air-dry for a few hours until it is mostly dried.
    •Mix the soil in the bag to ensure a homogenous sample and then use a sieve with approximate 2mm spacing to remove any large soil clumps.
    •Measure out ½ of a cup of the dried soil and put into a glass beaker.
    •Measure out ½ of a cup of distilled water and put this into the glass beaker with the soil.
    •Stir the mixture gently for 30 seconds. Do not mix to harshly as you may destroy the humus structure and the soil may give up elements that it otherwise would not do in nature.
    •Let the soil-water suspension stand for 30 minutes.
    •Stir water gently again before taking the EC measurement.
    •Insert the EC meter into the beaker and swirl it gently around in the soil-water extract.
    •After approximately 30-60 seconds or after the EC reading has stabilized, read the digital display on your meter.

    Ideal EC Levels.

    It is difficult to say what your ideal EC levels will be because there are so many variables affecting the EC level that it almost depends on your individual conditions which if you analyze over time, will give you a meaningful set of data based on the performance of your crops and the changes you have made to your fertility program.

    As a general guideline however, a good soil EC level will be somewhere above 200 µS/cm and 1200 µS/cm (1.2 MS/cm). Any soils below 200 means there is not enough nutrients available to the plant and could perhaps show a sterile soil with little microbial activity. An EC above 1200 µS/cm may indicate too much high salt fertilizer or perhaps a salinity problem from lack of drainage so keeping your EC within this range. Also watch to see how EC changes over the growing season, you may see it increase as microbes are releasing more nutrients from the soil or you may see a decrease as your crops use up all the available nutrients. Either way you can fertilize accordingly.


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  3. #52

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    Quote Originally Posted by jobby2812 View Post
    Pass but I never noticed any difference between the hps I was using and the hps dual spectrum I brought last year. It's a Sunmaster 250W Dual Spectrum Grow Lamp - 33000 Lumens that I used last year and have brought again for this year. Plants seem to love it for the first few weeks then things seem to go tits up.
    If the blue light thing is involved then that's probably what I'd expect when switching to HPS.

    Can you add some blue light somehow? Maybe just a cool-white/daylight fluorescent would suffice?

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  5. #53

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    Quote Originally Posted by GREENBUDDHAKUSH View Post
    Its mainly becouse the people in the thread agree that ph is need,Along come those that dont,and off we go again,and the thread was set up for the purpose of ph,Not just someones thread that the ph discussion got going and went wrong.Im finding this thread very educational,With great information that make sense,on a level i can understand.
    Sorry I disagree m8, I think the non ph growers just keep out the way now or they face a lecture I do agree there's some very good info in here tho'

    C.W. has stated in this thread, post #24

    "i also rarely need to check it or do run off tests anymore. ive got to know my water and food and what dose takes me to roughly what ph...at times is how i decide what dose to feed so no ph needed."
    What I have stated about not phing is exactly the same! I've been working with the same soil medium and nutes for two years and have learned how to use them properly instead of running to the hydro shop everytime I see a bit of yellow. My current girls are in their seventh week of flower and they're all "green as a bullfrog, sticky as glue"

    @C.W. I'm not having a pop at you m8, your writings are very interesting and I have learned things from it. Successful growing imo is more about experimenting with what you've got rather than try and work out what others have got/done and trying to apply it to your own grow! I read your diary and your plants are lovely specimens but I reckon your ph/ec meter would would cost more than my whole set up

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  7. #54

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    I love a good lecture,What better way to learn,As an adult i think i can take a good shooting down without crying about it, and take it on the chin,Im looking forward to the day when I have the experince and confidence not to use PH and EC equipment,But i still need to learn how and why and when and where ................................

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  9. #55

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    that blue light info is interesting. i dont think thats his issue or how accurate it is in the actual grow world vs a book. ive used straight up hps all red from the 70`s to 80`s and never had the bulbs cause the lightening or the issues described here. it could still do some. how much.,..who knows. blue and reds do effect alot of things like hormones and so on inside them so the colours do make an effect but to what extent who knows. if more had same issue with same or similar type bulb id tent to lean to the bulb but i dont see that. and to be honest i dont know of to many bulbs anymore than are just red for hps/...yes some but its faded out of the industry quite a bit...except for reg old security lighting bulbs

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  11. #56

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    Quote Originally Posted by Up_in_smoke View Post
    It sounds like you're underfeeding a bit buddy.
    They should take 3-4 days between waters and if thats final pot size we're talking, 1 litre of water wouldn't be enough and this will be why they're thirsty after 2 days.
    For a final pot (15-20L) in soil under a 600 I feed 5L per plant per feed from about week 2 flowering. In mid-late veg they get a minimum of 2L-3L.
    You need to be watering slowly until you get runoff out the bottom.

    sound advice on water amounts. we need to slowly use more and more till our root masses have filled our medium. then we can about dump any amounts in there and they wont droop. when younger and not full of roots it would drown them and slow them..and doing that can and does mess up pH..being to wet to long

    for me im in 2 gal pots, under 2x600 and i get 1 day to 2 days max of no work on them as far as feed or water....but thats me. we all do diff amounts. i feel 3 to 4 days is to long to be wet unless in something like a 10 gal pot and thats way to big for any grows in here. unless they veg for like 6 or more months

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  13. #57

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    actualy tic tok the pen i use now cost me 50 bucks. i gave ,my 600 dollar ,meter away to a needing friend. to be honest i trust the cheeper one alot better....blue labs sucks in my opinion. cost deffinatly dosent mean quality. ive used a 20 dollar pen for years and been fine to.
    wasnt taking it as a poke dood. some of us like to know and some are ok with close and guessing. dosent make either wrong. and how i see is if they dont even bothger to try then they will never know if it helps or makes more better buds for them.

    and fo rme reason i dont need to check is i know my water is perfect each day. you guys dont for the most part, mine gets filtered so outcome numbers are exact each time. water source plays huge role on pH and can be different daily

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  15. #58

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    i dont know anyone good enough to never have a use for ph pens. they may think its ok but nobody can grow perfect. most issue we will never see above the soil but they happen

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    if theres any info or stuff i post and some dont get certain info or the whole thing, just say so and i dont mind trying to explain it different ways.

    i see alot looking in the medium for ph effects....some should look above as there is alot above that will also effect ph....stomata.

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  19. #60

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    Quote Originally Posted by C.W. View Post
    that blue light info is interesting. i dont think thats his issue or how accurate it is in the actual grow world vs a book. ive used straight up hps all red from the 70`s to 80`s and never had the bulbs cause the lightening or the issues described here. it could still do some. how much.,..who knows. blue and reds do effect alot of things like hormones and so on inside them so the colours do make an effect but to what extent who knows. if more had same issue with same or similar type bulb id tent to lean to the bulb but i dont see that. and to be honest i dont know of to many bulbs anymore than are just red for hps/...yes some but its faded out of the industry quite a bit...except for reg old security lighting bulbs
    HPS, as a generic source, is very short on blue wavelengths. They do emit some though, so with sufficient intensity the plants may receive enough blue. This may be why it doesn't affect plants grown under high illuminance levels, and could be why it hasn't happened to you.

    "Dual-spec" lamps try to address the issue somewhat but whether it's sufficient or not, who knows?

    The red/blue thing is, as you say, important and affects the photomorphogenic responses. The normal 'an excess of blue reduces stem elongation', and 'red promotes flower growth', and all the rest. One of those things is that without enough blue light the plant won't be able to make chlorophyll.

    I strongly suspect that for HPS growers (and especially those using less-than-optimal illuminance) who have plants exhibiting yellowing leaves, the lack of blue is a contributory factor. As far as I can tell, it certainly seems like it happens in those situations more than any other.

    And, mostly, the topics and posts and recieved wisdom is that either "the plant is eating itself/using up stored food" (which doesn't really happen in real life, outdoor plants of most descriptions), or that there's a deficiency or pH issue. The thing is, I rarely, if ever, see it solved. After mucking about altering this, testing that, and changing the other it's usually down to the fallback, "they always do that near the end". Now that may be true, but is that actually "normal" behaviour, or is it caused by a lack of blue light? And if it is normal, why don't all plants do it, rather than just some?

    It's definitely an an interesting question, but the more I see and the more I read, the more I'm swayed towards the idea. It's simple, elegant, is supported by observational and biological/chemical evidence, and it's a relatively easy thing to fix or test.

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