Hi, I use organic soil, the following mix: 53% Organic potting soil 25% Perlite 10% Vermiculite 12% Worm Castings My nutes: BioBizz, I use BioGrow, BioBloom & Alg-A-Mic. The strain is Jack Herrer. I use RO water for irrigation (TDS < 40). Plants are growing pretty fast, but almost from the beginning there are signs of deficiencies - paling leaf tips and also the tips of the serrated "teeth" along leaf edges. Leaf edges curling up.... Pretty early on the pH starts trying to escape the earth's gravity. It goes over 7 and keeps rising. I was pH-ing my irrigation water to 6.2, then to 6.0 (using GHE pH down - nitric & phosphoric acids), with no effect. Tried flushing the big ones that are in bloom - flushed a 3 gallon pot with 9 gallons of RO water, and the pH wouldn't budge. Stayed at ~7.3. I pHed my water to below 6, nothing. I've spent days searching the forums & reading about pH and other issues, but I'm still clueless. How do I bring the pH to reasonable levels? Thanks, FR>
Type "vermiculite ph" into google. Read the info starting with the top page. If that's the problem, I dunno how to fix it other than to use a different soil mix next time.
This is very good to know, and I guess I should test my vermiculite, but I don't think that is my problem. Before I used a different type of potting soil that was quite problematic and acidic. Added the same verm to that soil too, and the pH stayed low. Now I have one plant in that same soil, while all the rest are in the mixture I have described below. And its pH is skyrocketing as well. I changed only one thing: added WAY more worm castings (12% instead of one tablespoon per gallon). Could that be it?
Are you saying the one with more Worm castings has the worst pH fluctuation? It's pH is increasing faster? How are you testing pH? I've had alot of experience correcting the pH of fertilizer teas and you might want to try something. Prepare your normal fertilizer mix and any other fertilizers you give the plants (separately). Test the pH and make a note of the values. Let the fertilizer sit for at least a day and test it again. Let it sit another day and test again. See if the fertilizer solution's pH changes. If it does, it's not an uncommon problem.
There are many situations where the soil and/or ferts change pH over time. For one, microbes will change the pH as they do their work. Secondly, there are many substances that don't immediately dissolve in water but can when given time. These also change pH. This constant pH fluctuation is unavoidable but manageable. The soil of all my flowering plants ends up too alkaline by the end of flowering because of the very alkaline ferts I use. The plants still turn out very well because I adjust waterings and feedings to compensate.
OK man, I think I'll go for a black belt in pH. See, they won't let me get stoned until I do. Buggers. Anyways, I will certainly run the tests you propose. I did the same with my tapwater, in those heady old days when I was using it for irrigation, and the results weren't pretty scary. I needed about 8-10 drops of pH Down per litre to bring it from 8.0 to 6.2, and it would rise to around 7.0-7.2 in a day. More pH Down, and in another 24 hours it'd rise again to 7. All my pots currently contain soil that has the same percentage of worm castings - 12%. I have one pot with old, slightly acidic soil, which I used for consistency. And that same soil mixture would stay with low pH throughout the growing cycle, even though I had tried (gently) to raise it. Now, I've changed one thing and one thing only - added more worm poo - and voila. Not fluctuations though, it's just going up & up. I use chemical testing kits for aquariums to test my pH. The ranges they can measure is between 6.0 & 7.6 for one and 7.4 - 8.8 for the other. So if I wanna go below 6.0 I extrapolate and drop a prayer to Poseidon. I've been reading in the forums. Some say you measure the pH of the very first drops of runoff from the pot (most accurate), others say you measure runoff pH at the very end (most accurate) and yet others say runoff pH is completely immaterial. In my case there is almost 0.5 points difference between the two, with the first few drops being lower. BTW - do you flush? Several sources recommend doing a good flush once a month or even every few weeks. I know many local growers flush before flowering. The plants I've flushed a couple days ago seem to have picked up, in any case. And one last question: when you're in advanced bloom and pH is getting high, what pH water do you give it? What do you use to bring the pH down?
Btw, always cover the liquid you're letting sit out. Dust alone will change the pH if a liquid is left out in an open container. I've had to use the exact same type of test drops and they're terrible for growing. For the same price, wide spectrum pH drops can purchased that show a range of at least 4-9. As little as $5-10 at garden stores. The best way to find good local garden stores is to separately type in "Garden Center" "Hydroponics" and "Nursery" into Google with your zip code after it (or city name, etc.). Click on the little map, call the closest & best rated garden centers and ask about wide spectrum drops. To get an accurate reading of soil pH using test drops, you need to use pure water tested at pH 7. Wet the soil thoroughly but without too much running out the bottom, you don't want to flush them. Let the water sit in the soil for at least an hour and then squeeze out some liquid to test. You can either grab a handful of soil and squeeze a few drops out or press on the soil surface and collect the runoff from the bottom. The runoff that comes out when you water hasn't had time to take on the pH of the soil yet. Only flush when there's a problem or as the last watering before harvest. Flushing washes away all of the nutrients in the soil and if the plants were fine before it, they'll be deficient afterward until the soil dries & the plants are fed. Anytime there's a toxicity in the soil, flushing can be helpful. It can usually also wash away pH-altering substances and so is also used when the pH is way off. If the pH is only off a little, it's neutralized with liquid of the opposite pH. Usually a liquid is used that has a pH the same distance from 7 as the substrate is, just the opposite direction. If it's way off or requires regular neutralizing, the substrate is flushed. I use pH Down crystals for major pH adjustments and lemon juice for small adjustments. Since most of my ferts are alkaline, I don't need any kind of pH Up.
I think alkaline ferts would lower pH over time.... as explained in the "pH Manifesto". And the flushing I did 2 days ago definitely improved the condition of my plants in bloom - literally more trichomes, really nice to see : ) There's no way I can get pure water of pH 7. The distilled water I used to buy is 6.2. My RO produces water of 7.4. All you need to do to get it to drop to 6 is to look at it angrily.... I live in Israel. We do not have shit here. Hell, I'm trying to get my hands on some perlite these days. One place in (a very big city nearby), the only nursery that even HAS perlite in this city sells it for 3 bucks a gallon. Yeah. We have a hydro store chain here.... I only go there because nobody else even carries any professional growing equipment. They are overpriced and the salesmen lie to you, even when they don't really have to to make a sale. And they sometimes have perlite, the white gold.... I am glad I do not need dolomite lime. Because the only way for me to get it would be to order it on eBay (again, YEAH) or produce it myself, which I have considered. Need to brush up on my geology. Anyways, can't rant too long about Israel when I am stoned. When I flush, the last gallon of water I give the plants has a moderate nute mix added to it - grow, bloom & algamic. Today I flushed the last batch in bloom and I added a low dose of epsom salts to that mix. Something tells me I will not regret it. The pH test tubes with the broad range are less accurate, I believe. Also costs 18 bucks at the hydro chain. Grown to trust the ones I'm using now. But I'll get me an electronic device as soon as my budget allows. Not in the very near future, I'm afraid. And finally, I've been suing a lower pH that what you recommended - 6 and a little lower lower - at the end of flushing, last gallon, and still got high runoff pH. hadn't been that affected by my attempts to correct it. FR>
Forgot to mention - I have pH Up & pH Down (nitric acid & phosphoric acid) from GHE. That's what I'm using to correct pH. This I CAN get here : ) At the hydro store.....
Oh, and another thing - disconnecting my mouth right after this - I intend to get me a fancy airstone for my reservoir (about 16 gallons), and then I will be able to keep it closed while letting it breathe, and it will be a lot more efficient this way. I'll borrow a motor from a friend
That's interesting about the worm castings. Do you know what the worms were fed? I think I, too am having a problem with high pH now, but not sure because my meter is crappy. (Don't waste your money on a Milwaukee pH 600 - the cheapest electronic meter you can buy. Mine won't stay calibrated for 1 minute.) Anyway, I am also using a lot of worm castings (like 20%), but I used the same worm castings on my last plant and didn't have a problem. I have noticed that when I let my tap water sit out exposed to air for several days it becomes acidic. It's about 7.4 out of the tap and after a week it's about 6.4. It's probably because of the reaction between the CO2 in the air and water -- this creates carbonic acid. (H2O + CO2 --> H2CO3) I've been capping the bottles after two days, so the water doesn't have a chance to get acidic. I'm going to stop doing that. About the perlite -- if you can get some sand, preferably coarse sand, it does the same job. It's a lot heavier, though. You might be able to find sand at builder's supply stores. If you can dig some sand up outside you could sterilize it by heating it in the oven. Not sure what temperature, but you could google that. Good luck.
Yeah, I'm thinking about sand. I'll try to get some perlite again first. My water comes out of the tap at 7.4 and rises to 8.0 after 36 hours. I think that if your acidity actually drops over time, it means your water is low on alkalinity, which is good. But only a full water analysis will show the real picture. A TDS meter could also improve your understanding of what's going on. I've heard good things about HM Digital (TDS & pH meters for water). Cheap is always more expensive in the long run - a 30 days warranty, that's rich! I've been meaning to call the guy who's producing the WCs I'm using. I'm using a very expensive type, hope it's really worth the money. I understand that the "microherd" in the soil can affect pH, plus the regular metabolism of the plants would usually increase pH. This article explains a little about nutrient pH and how it affects soil pH in the long run. http://growersunderground.com/pH_Manifesto.pdf Good luck to you too mate, FR>
This thread: How does VERMICULITE affect pH in soil? - Cannabis Culture Forums Has an interesting passage on pH adjustment. Also worth reading: http://forum.grasscity.com/advanced-growing-techniques/330991-fertilizing-wisely.html http://forum.grasscity.com/absolute-beginners/567829-ph-what-means-your-plants.html
Also thinking of infecting my next batch with some fungi The Pensacola Florida Rose Society BioVam Treated Roses brochure.
probably not putting this correctly but here it goes someone once told me that in soil if you flush everything out you can have problems like the PH going way up over night and not staying normal something about it removing something that makes it stabilize properly - you can put 6.0 in there and even read 6.0 run-off but in 12 hours or so it will be up over 8.0 for some reason I am probably wording this wrong or maybe even wrong all together but I have had problems with plants that I flushed with 10's of gallons of water to bring things back to normal
Humin or humic acid? I know they stabilize pH. So add it in liquid form. If you have high TDS you must flush. If you don't flush you might as well stop watering, 'cause the salt buildup will kill your show. Oh, and I think the only way I will read 6.0 runoff is if I pour the pH down directly into the pots : )
I've just flushed the frog out of a couple of 5 week old clones. They had been repotted into 1 gallon pots a week ago. Used RO water with 1/2 ml Algamic / litre and a little pH down. Runoff was around 7.2 at first, then rose to 7.4 (after about 2.5 gallons of water had gone through the pots). At the end I fed it with a mild fert mix prolly around pH 5.0. Runoff was 7.2. Fun. I've also taken two samples of vermiculite (from 2 different bags purchased.... not sure if at the same place, but at an interval of several months). Watered them with pure RO of pH 6.6. The verm don't hold water too good. Well.... I tried giving it a little at a time, and eventually decided to measure the pH of what was coming out the bottom. 7.5-7.6. Cloudy - full of dust. So I'm gonna keep irrigating those two samples, soon I'll flush 'em, watching the pH as I go and I think I'll be leaving vermiculite out of my soil mixture for now and possibly for good. Jellyman - rep up, mate, & many thanks! FR>