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The importance of BUFFERING

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    COCO COIR The importance of BUFFERING

    Growing in coco coir

    This post is for all of you soil growers or first time growers that want the benefits from growing hydroponically but without buying lots of new equipment and run a noisy air pumps etc.
    You should know there is a passive hydroponic substrate just for you;
    Coco coir!
    With coco coir you’ll get quicker growth in the vegetative state, maybe not as fast as a true dwc setup, but it beats even the best soil setup easily, and it is my experience that your yields improves quite a bit too. The main reason for this is the improved and increased oxygen level at the root zone (Healthy roots is the #1 concern for healthy plants and heavy growth) and the direct feeding of nutrients.

    Coco is a completely organic substrate, made from the fibers in the coconut husk. It is reusable, to an extent, and you can use both mineral and organic nutrients with it.
    The light weight (when dry)makes it easy to use and process.
    It has great water holding capability but also holds a great amount of air in the fibers which makes for a great environment for your root system and the micro life. With coco it is virtually impossible to overwater your plants, unless you really aim and work for it. It comes to its best rights when used together with air or smart pots, but it works great with ordinary pots as well.

    First of all, you need to decide what kind of coco you should use, what brand and type works best for you?
    There are a huge amount of different brands of coco coir out there and choosing can be hard.
    Understandable, I haven't tried them all, but I have tried a lot of different brands and types and have learned what works best for me and my plants.

    Types of coir

    Are you a beginner and are looking for the easiest coir to start, or maybe just want the quickest?
    Then the pre blended and pre buffered, ready to use kinds, like "Gold Label Special mix coco" is what you want.

    This was the first one I used myself and is very easy to use for a former soil grower or first time grower all together.
    Just like with soil, you can just pour it in your pot and start grow, but for better performance you should lighten the mix with perlite or/and clay pebbles.
    Although this type of coco coir has a lot of "pro's", it also has some "con's", for example, the "Gold Label Special mix coco is quite finely ground which is not so good mainly for the following reasons:
    1. Coco coir with mixed coarse has better air holding capabilities.
    2. Fine ground coco decomposes quicker and therefore has a shorter lifespan.
    The fact that it is moist also speeds up decomposition.
    3. The package gets larger and heavier, which often means increased shipping charges.
    4. It is usually more expensive.
    5. For experienced coco growers it is more beneficial to do our own buffering, with pre buffered coir you never know exactly how stable the buffering is and how it's done.

    Next, you have the Coco bricks, dried and compressed coir which comes as a hard block, roughly compressed to 1/10 of its original size.
    Sometimes it comes as small bricks with 10 liter coco each and sometimes it comes as one large block which you will have to measure out and cut before processing (or do the whole block of course).
    This is the kind of coco I use today and have used for the last couple of years.

    This type you need to soak and buffer yourself.
    Even though many of these brick type coco coir state that they are pre buffered, they obviously lie, as buffered coco needs to stay moist to keep its "charge". What is important though is where the coir comes from and that it is properly washed to remove all salt contents.

    What is Buffering?
    The adjustment of the cation exchange capacity of grow media, referred to by many as the buffering of grow media, is a subject that most hydroponic growers could benefit from knowing a bit about.
    To help us understand the principles behind caption exchange and buffering it is best to use an expert on the subject;
    Mark Wittman provides growers with a technical look into this process and how buffered media has a big impact on what you feed your plants.

    This is in no way anything you need to learn and remember from the top of your head, but it is a good idea to get an understanding of the processes in the media and how adequate buffrring helps your crop thrive and get the nutrients it need. Badly buffered coco can give you huge amounts of problems. I have experienced badly buffered coco first hand, in my early coco growing days. It gave me big problems troughout the entire grow, but luckily, after much hard work, I harvested a nice yield of premium bud.
    If I didn't have the experience I have and the help I get from my friends at “Crop Doctors” I doubt I would get any yield at all from that grow; that's how hard it got, just because I lacked knowledge and failed to see the importance of proper buffering techniques.

    Wittman's words;
    The widespread use of calcium and magnesium supplements in the indoor gardening industry is an indication that many growers have discovered the cation exchange capacity (CEC) phenomenon in coco media. Growers are observing deficiencies and trying to correct those deficiencies with calcium and magnesium supplements. This article explores why these deficiencies happen and how adjusting the cation exchange capacity, or buffering, the media corrects this problem.

    Coco growing media has changed a lot in the last decade or so. Previously, the majority of coco products were washed to an EC of 1 or 1.6, and few products on the market were buffered. Today, the higher-quality coco products are washed multiple times and will have an EC of 0.5 or lower. They will also be buffered in some way or another.

    Coco Cation Exchange Capacity

    Soil particles and organic matter have negative charges on their surfaces that attract cations. The total of these negative charges are collectively referred to as the CEC. The CEC is significant in growing media because it is a measure of the quantity of nutrients the media is able to hold on to before nutrients start leaching out. Plants are able to access the cations attached to the cation exchange capacity.

    Coco often has a CEC in the range of 90-100 meq/100 g of media. The CEC of coco is naturally loaded with potassium (K) and sodium (Na), with little or no calcium (Ca) or magnesium (Mg). These are the four cations that are most important when buffering coco.

    The goal is to significantly lower the percentage of CEC sites that have K and Na on them and increase the percentage of CEC sites that have Ca and Mg attached. Potassium can be attached to up to around 40% of the sites and sodium can be attached to up to around 15% of the sites. This is significant because if 40% of the exchange of un-buffered coco is holding potassium, then that equals 40 meq/100 g of media of the single-charge K molecule.

    The 100 g of weight in the above equation is the dry weight of the coco, not the weight of the coco straight out of a bag when it is moist. Hydrated coco should make 12-15 L (3-4 gal.) of coco growing media per kilogram of dry coco and of course 100 g is one-tenth of a kilogram. This does not sound like much, but would be as much as 1.56 g of potassium per 100 g of media. This is a lot of potassium, most of which will be slowly released into the aqueous solution around a plant’s roots. Compare this 1.56 g to 0.22 g of potassium per liter of nutrient solution (which is feeding potassium at 220 ppm, the amount that one would have in a well-balanced feed). If you have a 4-gal. pot and give it 1 gal. of feed per day, you would be feeding about 0.9 g of potassium and the CEC may be holding 15.6 g of potassium. Sodium may be present in up to 0.35 g per 100 g of media. With these numbers, an unbalanced nutrient solution will quickly result, as I explain in more detail below.

    Coco Buffering

    Buffering coco media is accomplished by exposing the cation exchange to a solution of water with a high concentration of the cations that are desired on the exchange sites—in this case, calcium or calcium and magnesium. Because the cations on the exchange sites are held reasonably tight, washing coco does little to change the makeup of the cations on the exchange sites. The washing will change the EC but not the CEC. CEC sites have a preference for some cations over others.

    If the cations of Ca, Mg, Na and K are all present in the solution at the same concentration, they will be adsorbed at different levels, with calcium and magnesium being adsorbed at double the rate as they both have a double-positive charge, while potassium and sodium have a single-positive charge (Ca++, Mg++, K+, Na+).

    For example, many coco product manufacturers buffer their coco with 8 kg of calcium nitrate per cubic meter of coco. Calcium nitrate has a value of 19% calcium, which equals 1,520 g of Ca with almost no Mg, K or Na if the water is clean. As the process commences, a high concentration of Ca molecules attaches to the media—as each Ca++ molecule is adsorbed, two molecules of K+ or Na+ are released because the Ca has a double-plus charge and K and Na are single-plus charges. In the beginning, the exchange goes very quickly, but as the exchange continues, the concentration of the K and Na molecules released into the solution slows the exchange down and it will eventually come into equilibrium. The buffering process can be done in 10-15 minutes—the point at which the exchange slows down enough that the greater exchange is not worth the wait.

    Some coco products have been buffered with a higher treatment of Ca and Mg concentration. This creates a lower K and Na percentage on the exchange and adds the benefit of Mg to the CEC. These more advanced buffering processes involve a much greater amount of time, but result in much lower K and Na levels on the exchange. This essentially creates a better coco product from day one, ensuring all of a nutrient mix goes straight to the plant versus amending the coco’s CEC.

    What Does This All Mean for Growers?

    As a grower, your goal is to create and use a well-balanced nutrient solution. If you are using an un-buffered coco product, a well-balanced nutrient solution goes into the coco and starts to buffer the coco as well as feed the plants, instead of all of the nutrients going directly to plants. So, the CEC in the coco is exchanging some of the K and Na for Ca and Mg. This exchange is now unbalancing your nutrient solution, increasing the K and Na while decreasing the Ca and Mg. How much unbalancing, you ask? Earlier, I mentioned the coco could have as much as 1.56 g of K and 0.35 g of Na per 100 g of coco. Your nutrient mix is not highly concentrated with Ca and Mg, but it is enough to get some of the K and Na released from the CEC.

    About 15 years ago, I was growing roses in coco and we did a weekly chemical analysis of our feed and drain water. The first time we used coco, we noticed the Ca in our drain water was less than 40 ppm (we would have normally expected the Ca to read 100-150 ppm in the drain water), and we were feeding Ca at a rate of about 200 ppm. For the next two weeks, we had the same result, so we doubled our Ca to 400 ppm. The analysis of our drain water went up to about 50 ppm of Ca. We watched that for about three weeks and then started feeding Ca at about 500 ppm and still had very little change in the Ca ppm in our drain water. It took about four months for our drain water Ca analysis to read about 100 ppm. The loss of the Ca and Mg is one thing, but you also get an increase of K and Na. High levels of K will hinder the uptake of Mg by plants. Sodium can negatively impact plant health even at low levels and is toxic to some plants starting at 50 ppm.

    The widespread use of calcium and magnesium supplements in the indoor gardening industry is an indication that many have experienced the CEC phenomenon in coco that I am talking about here. The deficiencies are observed and can be corrected to a certain extent with calcium and magnesium supplements, but there are also coco products out there buffered to a higher level, which don’t need the calcium and magnesium supplements.

    A Coco-Buffering Glossary

    Cation Exchange Capacity (CEC) – The degree to which a growing media can adsorb and exchange cations. The value of a cation exchange capacity is normally expressed as meq/100 g.

    Cation – A positively charged ion, such as Ca++, Mg++, K+, Na+, NH4+, H+, Al+++.

    Milli-equivalent (meq) – A measurement often used in quantifying a cation exchange capacity (meq/100 g = milli-equivalent per 100g of dry media). The milli-equivalent is based on the value of an equivalent. An equivalent is the weight in grams of a molecule divided by its molecular weight multiplied by its charge. For example, hydrogen (H+) has a molecular weight of 1 and a single positive charge, so 1 g of hydrogen is one equivalent. Calcium (Ca++) has a molecular weight of 40 g and a double-positive charge, so 40 g of calcium is two equivalents.

    That is about all the comp grower needs to know about what buffering is and why we do it.

    The second most important thing with coco, or essentially just as important, is how to treat your medium so that it keeps it buffering as well as making your plants thrive like never before.

    Watering and pH levels:
    To make sure the coir keeps it's charge/buffering and to keep the desired pH level it needs to be kept moist at all times. Never let the coco coir dry out in between waterings. The coir holds plenty of oxygen for your roots to thrive and grow even with the media soaked, and with perlite mixed in the environment are perfect no matter how wet it is. Every time you water your plants the water pulls down microscopic air bubbles which re-ariates the coir, so it is important to water the plants at least once every day, if you grow very thirsty plants under hot conditions you may have to water more times per day to keep the medium from drying out, then do so.

    I'm my first year or two of growing in coco coir I did this all wrong. Previously I was a soil grower and I was looking to improve my harvest, didn't really wanna go dwc since a friend of mine who did ended up with huge root-rot problems, and that kind of bummed me of.

    Instead I went for the coco coir, it was cheap, no need to change the setup and basically worked just like soil.. I thought. And it kind of did…
    Just like I did when I was growing in soil, I was careful to make sure the “soil” dried out between watering, but that's a big NO-NO. This will only result in toxic salt buildup in your media, and its almost impossible to flush out. So to avoid this, make sure your coir Never does out, even if it means you will have to water twice a day. You can count on watering at least once a day, from start.

    Good luck, and may all your birds grow big, fat and tight!
    Last edited by braincrash; 08-31-2018, 07:33 AM. Reason: Added tags and info.
    Marijuana is no drug, it's a human right!

    braincrash Thats great advice and incredible detail thank you for explaining something I had not considered and I know now why when I have seen other growers having issues when using coco coyer it’s solely for the reasons you mention, either coco was not buffered or not correctly buffered, and or letting the coir dry out as if using soil..

    I am growing in soil at the moment but originally wanted to do hydro. After looking into the options, I decided that I really wanted to try growing in coco after this soil grow, so this information is so valuable to me at this time and will be a great tool for me to use when I do begin to use coco for the first time..

    Again many thanks .


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