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Feeding plants in coco.

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    Feeding plants in coco.

    Am I supposed to be feeding my plants in coco nutrients every day?

    I don't - there are many ways to get good results in coco.

    I do not want to let the pot dry out, beyond a couple of inches from the surface.
    (unlike soil grows, when you get the pot light and dry, before the next water/feed)
    It's all bullshit - until you smoke it!

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      To get the best results, Coco/Perlite should be kept wet. Even at field capacity (fully saturated) the combination of Coco/perlite retains sufficient O2 in the root zone to promote healthy growth. It is practically impossible to overwater plants. If it were possible, my plants would be dead...
      On the other side, when Coco does get dry it really limits the amount of water available to the plant. Plants will survive and grow respectably if you treat Coco like soil, but they will not grow to their potential.

      I posted this on your other thread but will repeat here:
      I always give one big water per day. To saturation on days with nutes and to 20% run-off on CalMag days. Late in Flowering they increase water use and I will notice the very top of the coco gets dry by the end of the light cycle. When this happens I give them a supplemental watering before putting them to sleep (Usually just 1/2 as much as during their normal watering). My philosophy is to never let the top of my coco get dry. For most of the grow one watering per day suffices.
      In terms of "Feeding", I recommend at least every third day/watering be without nutrients.
      I put together my own nutrient schedule that I am following on my current grow. It is below FYI


        You should water coco every day. That's non-negotiable. I don't think most people feed every day, but I do since I think a steady supply of nutrients is better than feast/famine (though I'll be the first to admit there probably isn't much difference between feeding daily and feeding every third day).

        For daily feeding I give the full Nebula schedule dose of CaliMagic (12.5 ml gallon) since we have no minerals in our water and FloraSeries diluted to 60% of Nebula's already diluted version of the GH schedule.

        That's 200 PPM Ca/Mg + about 185 of NPK/trace elements. My nutes recirculate into a 6 gallon reservoir and are changed weekly, just like hydro. Hope that helps--not a recommendation so much as a reference.

        See Nebula's coco grow article for a proven method:


        • Campesino
          Campesino commented
          Editing a comment
          The money quote from the above link

          "We don’t recommend letting the coco dry completely between irrigations. The plants respond better if you provide a constant level of moisture. If your substrate mixture contains a decent amount of perlite (25%) which helps the mix drain, overwatering shouldn’t be too much of a threat, so don’t be afraid to water on days even when the coco has only slightly dried. It is important to note that this “back-and-forth” between moist and dry conditions is very stressful on plant roots."

        • Campesino
          Campesino commented
          Editing a comment
          BTW DoctorJohnson The link I posted completely agrees with and validates your approach. You may want to hold on to it for later use!

        • St.buds
          St.buds commented
          Editing a comment
          Awesome campesino thank u!

        > BTW DoctorJohnson The link I posted completely agrees with and validates your approach. You may want to hold on to it for later use!
        That was a good read. (And it's nice to have your personal theories validated, though as I've said, I really got it from the orchid growers who fertilize often with weak nutes in non-nutritive solution.)


        • Campesino
          Campesino commented
          Editing a comment
          After spending the last couple days reading extensively on Cation exchange properities and Coco, I am going to switch to daily feeding with no "just Cal Mag" day.
          The science here is supporting that 100%
          Flushing with straight water seems to be little more than a learned practice transferred from soil. It is actually inappropriate in Coco!!! Wow - Learn new things all the time

        I have spent much of my time this weekend reading about Cation exchange capacity and salt and water retention properties of Coco and Coco/Perlite. All scientifically rigorous sources concur… Coco not only doesn’t need the plain (or cal/mag) water interval flush between nute feedings – It should not be flushed like that. Plants should be exposed to more consistent levels of nutrients to promote rigorous growth. Coco does not hold on to salts like soil which obviates the need for these flushes. The same nutrient water will flush out the excess salts. Rather than flushing alternately with plain water, all water should have nutrients and be applied until at least 10% run-off. That run-off is needed to keep ec in line and allow those salts to flush out.
        I had a hard time believing what I was reading, but all sources that actually discuss the science of CEC agree that Coco/Perlite should be fed nutrients with EVERY watering!
        Below, I include links to some of the interesting online discussions that are publicly available (I did most research through a University Library and cannot easily share that)

        Coco Feeding/Watering Conclusions I am confident in making at this point:
        1. Coco/Perlite should be 60/40 to 50/50 (if it’s not the rest does not apply exactly)
        2. Coco/Perlite absolutely SHOULD NOT be allowed to get very dry. Dry Coco stresses plants more than dry soil.
        3. Coco/Perlite should be allowed to dry somewhat between waterings, but not so much that the top layer changes to lighter brown. Light brown coco is sign pot is too dry. On the other side, continuous drip feeding is also not recommended
        4. Daily watering is suggested as a starting point. Only in very large containers does anyone recommend possibly less than daily watering. On the other side, some claim you should use small containers so that you are able to water 3-4 times per day.
        5. All water should have nutes! The practice of alternating nute with plain water is important in soil where salts can build up and must be flushed. Coco does not retain these salts as well as soil and any excess salts are flushed with any water moving through the medium. It stresses plants to move back and forth from nutes to no-nutes, and although they can handle it, it is certainly not helping them grow better. Again, all of the scientific sources I found agree on this point. Here is another online link:
        I am unsure how to exactly adjust nutrient strength.
        • Assuming you were doing one day nutes and one day without, it seems reasonable to consider cutting nutes in half. Based on all this info, I think that cutting in half is probably too low and would reduce the amount of nutrients available to the plant over a stretch of time. Since I have already been going at 2 days with and only one day without I am thinking about adjusting my nute schedule to 75% of what I had been feeding on nute days (for most, but not all nutrients/additives). I am still working on updating my feedchart.


          I grow autos in 3 gallon containers. When the plants are young I will water every other day. Once they start spitting hairs, I normally up it to once a day. I also always water with nutes.

          When they are flowering and I go to water the next day, the top layer has dried out a little, but not completely. My plants seem to do very well with this method. I've heard of all different ways to treat coco, and I have seen good results with several different methods.

          If I water daily when they are young, I experience leaf curling, which isn't horrible, it just annoys me lol.


          Past Grows


            Im only just coming to grips with my soil science but botanicares reasoning does not sit right with my own understanding. Coir has low CEC. Clay and organics have the highest CEC levels. I wonder if its marketing tactics, wouldnt be the first time i have seen it.

            This is my current understanding so far in soil science, happy to be corrected if anyone here knows more on the subject. Looking at you KingKush

            Field Capacity And Water Availability:
            The field capacity is determined by particle size (soil texture) and porosity (soil structure). Larger particle sizes and higher porosity, allow for better infiltration rates and lower field capacity. Where as smaller particle sizes and lower porosity have poor infiltration and higher field capacity.

            The availability of this water is grouped as Hygroscopic, gravitational and capilliary water. Which depending on soil texture and structure, changes the water availability to plants and the permanent wilting point.

            Cation Exchange Capacity:
            CEC is the ability of soil to hold on to cations (positively charged particles) and describes a soils fertility. Plants can exchange hydrogen ions for these nutrient elements in the process called cation exchange.

            PH And Nutrient Availability:
            PH can actually change the CEC but its main attributes come from its effects on nutrient availability. Higher or lower PH changes the solubility of nutrients. Which appears to be from many reasons rather than one single entitiy. Such as precipitation.

            Based on this understanding it seems clear to me that the reason coir might not require flushing, is because of the fact it has LOW CEC. Being relatively inert compared to other soils is what makes it sought after as a hydropnics medium. If it had high CEC, that could reak havic as nutrients could potentially build up and cause havok. However it seems to have high affinity with calcium and magnesium and is the reason why its a common problem with the product. Which may also be why buffering is typically recommended.
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            • KingKush
              KingKush commented
              Editing a comment
              Coco is a hydroponic growing medium, simply a physical habitat for the roots, like hydroton or perlite or net pots, or sand... You can treat it like growing in soil, which is a comfortable and basic growing strategy that most beginners are familiar with, so it's popular. Plus, is shows an excellent repurpose of what would otherwise be waste. Low CEC also = CONTROL. It's easy to flush and there is low holding ability, So that can be used as an advantage.

              It's similar to growing grass over pure sand, or golf course putting greens which are constructed out of pure sand (newer builds or renovations). The problem lies in low or insufficient CEC in both platforms, sand putting greens & coco. Spoon feeding with frequent, light apps is the key to keeping nutrients suspended in the root zone. Daily, bi-weekly, or weekly apps are common even on a large scale, so feeding in coco every time would make sense.
              How we manage that into our program is to figure out how much of each mineral the plant uses each day. Usually it's Nitrogen (turfgrass is average .1lb/ week N) and then use just the right amount to get us to the next application. So it's like applying 15 days worth of nutes every two weeks/14 days, one extra day's worth just as a buffer. This would be my strategy for coco and it would look like pipettes of small amounts each time; perhaps that is a common theme in the need to flush all the time. Salt buildups are not an issue for programs that apply just enough minerals to sustain proper plant functions.

              I see Coco similar to hydroponics. Growing turfgrass on top of sand is a close second, which would be the most tangible blend of soil science & hydroponic plant biology to relate to. Low CEC is inherent to both growing systems, which is limiting but also liberating. We as pesticide and fertilizer managers must be aware of leaching phosphates and nitrates (NO3- , PO3-) in these systems. My concern is that 300acre golf courses next to streams, lakes, rivers, and oceans and under rainfall do a better job at keeping the environment clean than a bunch of potheads with 4 plant grows scattered along your block. So when I read about drain to waste it just makes me cringe because I understand the legal liabilities associated with proper waste disposal. We know we shouldn't put batteries in the trash but some of us do so, it's not like a cry out for this will change people's hearts. I don't grow in coco and I see very successful grows with this method so I cannot say "don't do this". However, if you went and did something with the rinsate like use it for your flower barrels then reward yourself for using your brain.

              Coco is a proven growing medium in which people find great results. I've learned much from watching some members grow in coco around here and I am very impressed. Wouldn't once think these people don't care about the environment, all of us around here seem like we care about plants and animals.
              Last edited by KingKush; 04-13-2018, 04:59 PM. Reason: Proofread

            • Campesino
              Campesino commented
              Editing a comment
              Agreed, the more I read the less botanicare’s reasoning makes sense, but the practice they suggest is still valid. Has more to do with keeping CEC satisfied or balanced which is constantly upset by adding water with different EC.
              But KingKush makes a powerful point and I now wonder about the environmental ethics of this again. Not only doing it myself but then promoting it to others as well.

            • DrPhoton
              DrPhoton commented
              Editing a comment
              Thanks king kush, happy to know i was on the right track.

            Recently, I have been feeding my plants daily with nutes. I have been adjusting the strength of the solution according to the difference in the ppm of the solution and the runoff. When the difference was greater than 200 ppm, I made daily adjustments in small increments until the difference was less than 50 ppm. This is where I am now. I'm staying at the current level until the runoff ppm is more concentrated than the solution, in which case I will reduce the amount of nutrients in my solution, or my plants ripen and I start to flush. I am very happy so far and will continue in this manner unless something goes bad. Just wanted to give an update.


            • Campesino
              Campesino commented
              Editing a comment
              Yes, inflow and outflow EC (or PPM, but EC is better) should be as close as possible. If outflow is higher than inflow, the likely cause is infrequent watering and can be corrected by increasing watering frequency (rather than adjusting strength). From my understanding, run-off EC should not go up on its own even as plants' needs change. The whole idea is to create equilibrium and it sounds like you have achieved it.

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