some plant issues

Think so? I water about every 3 days. Medium is pretty dry. Pots are light. Sometimes medium is separating from the sides of the pots. I water only to a little runoff too. I've been researching vpd because some photos I seen are exact matches.
 

hondagrower420

Well-Known Member
Think so? I water about every 3 days. Medium is pretty dry. Pots are light. Sometimes medium is separating from the sides of the pots. I water only to a little runoff too. I've been researching vpd because some photos I seen are exact matches.
No, she just tells anyone having problems that's what it is. Haha. She's a joke. Looks like cal/mag.
 

hondagrower420

Well-Known Member
Think so? I water about every 3 days. Medium is pretty dry. Pots are light. Sometimes medium is separating from the sides of the pots. I water only to a little runoff too. I've been researching vpd because some photos I seen are exact matches.
Sounds like you need to water more. Coco with plants that big should be watered like once a day.
Plants should dry it up pretty fast.
 

hondagrower420

Well-Known Member
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. 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.



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.
 

conred

New Member
My opinion is that humidity is a tad high ~40% is recommended; still, the problem isn't cell hydrolysis via belief that weight is no indication at all. Burned leaves strong yellowing and stem outward color says unless somehow magnesium has been never used or lacks severely. More
Likely, nutrients have burnt especially, no making of deficiency or hyper-water intake given a few leaves, some worse, most bright; although, based on the fertilizer all over the top of the pots. Shouldn't feed more than x2 per 14 days. Purified or distilled water can dilute whatever you've got an inclination to believe. I majored in organic Chem and pharmaconkinetics/dynamics, not so much botany. Zinc, magnesium, nitrogen are I'm sure in your feed. So over feeding I believe. Weight of leaves and stalks would droop down.
 

conred

New Member
Damn... That dude could've just clicked on the link that summary of all things growing, given the random info. Why not an opinion? The ppm and most wouldn't do that to a already knowledgable in the ppm of the h2o and relative humidity the commenter put on the question. Mg is a good idea. Depolarization of Ca2? Is this a stereochemistry nutrient? And why Na? I understand K, as well as (P2O5) and (Al)... Is that naming the ingredients...? Na is sodium and that's cations which would be for NADPH+ but protein cotransportation? ATP-dependent enzyme is more "plant" lol. I'm sorry that's just weird advice. Electrochemical gradient is beyond a sodium 'Na' super rich and splice because the affinity for high salt distribution. Saturate to hold water? It doesn't saturate it almost says saline is what I should use. Distilled h2o is a preferable watering tool because minerals and this is all about the material you suggest using? These, well the kinase ofprotein transporting enzymatic compounds hyper polarized elements wouldn't be able to transport in the sense bases once utilized are depolarizers and polar non-conductive. Why not get nutrient charges after absorbed.. Genetics would say Na means heavy water cell damage. It's cool if it's just a website. Didn't know if you worked in chemistry or bio fields. BTW don't burn all your fan leaves and possibly sugar if you do that. Human gene and hormones are the ATP of some plants but not this and not chemically needy like it may seem.. Energy polarized cations. Chemical compounds need a lot of energy to push solutes across cell membrane nvm cell walls in plants.
 

conred

New Member
I did not flush all of them. Only 3 that had obvious burn. All the rest have this issue. I have gone to water/feed/water/feed schedule.
Good thinking man. Sorry for the long answer before. It's hard to argue when someone pastes a confusing wiki page on here and judge the answers cynically.. You got some nice lookin kind. Hope the flush goes well. Does look like a magnesium boost is needed. I use a old chop stick to irate. Works like a charm Good luck. Happy harvest.
 

conred

New Member
I run cyco's full line. You would think that there is enough calmag in the product. The grow A & B have the calcium and mag.
Oh good shit so it is nut burn probably. Zinc and magnesium deficiency are very similar but I think it's too hard not knowing shit. Oh, she's just a person helpin out, you're the joke; well, no sht. She gave an answer.. contribute at least Copy/paste a damn relevant article. Potted question. Joke is a hydro substrate change for a different setup and I thought I could speak chemistry with you. Lol. You are the joke. Have any knowledge about a word in there? That is idk keep up the good ideas of more... original thoughts. happy harvest. Lemme know if saline works.. Ha
 
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