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Roodni

Measuring runoff pH

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Hi guys,

 

I am relatively new to growing in pots, and one thing I've had problems with since starting is pH.

I grow organically in soil-less (coco peat/perlite), and have always gotten problems with lockouts from too high a pH. I have been feeding at successively lower and lower pH's to battle this, but still the symptoms are there and after watering at 4.5 tonight and still getting a runoff of 6.5, I thought I would ask for some advice...

 

So, what runoff pH do you aim for, and should I try watering at a lower pH than this?

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6.5 is decent runoff... if you keep your PH around 6.0 it will balance out.

 

with coco peat, if you do not use PH balanced water from the beginning to soak it, it can be hot, and hard to balance out. nice work if you have done so without rotting out the roots or overwatering and killing the plants. i'd back off on the water since you are at a nice PH, and you should just stay on top of it from here on out. if there are no signs of nutrient deficiency, then clearly you have gotten away with it. critical PH imbalances will definitely show.

 

*in the future you can add dolomitic lime to your soil less mix... or use citric acid in your water to balance PH. those both help stabilize PH and create a buffer zone over the long haul, whereas some acids are quickly eaten and absorbed.

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Hey Roodni, I am not sure how accurate an indicator it is to measure the actual runoff, or water leaving the bottom of the pot. I know it sounds logical that it should be but i have often found it to be significantly different than the ph taken from the soil itself. I use soil but the same probably applies to your mix as well. It may have to do with rinsing out the waste/salts in the runoff which then affects the ph of the runoff water.

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PS: no... do not water lower than 4.5.

 

as low as 4.5 may shock them more than any minor PH imbalance you may have. if you post pics we can tell you if there is actually anything to worry about.

 

and runoff is not always an accurate indicator of soil PH, but i have not found an accurate soil PH measuring tool. for what it's worth it is pretty accurate in the beginning. later on you will have more mineral/salt build up, so it may not be. 6.5 is truly pretty ideal. if you are working with a premix, they probably knew what they were doing when they made it. ;)

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I've been dealing with pH issues also. In my case it was low soil pH. I think the soil mix must be amended before planting. In my case, I was not using any lime, and although my plants seemed to love life in veg., the pH would steadily drop, and I'd get some lockout in flower every time.

 

I think it is almost impossible to balance out soil with adjusted water.

 

Maybe you are adding too much lime in your soil mix? If you are not adding any lime, I don't have a clue.

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Buy a soil ph probe.

Some are not that great but they do give you a far more accurate soil ph reading than measuring the run off.

http://www.ebay.co.u...cat=0&_from=R40

 

You can even buy wireless soil probes if you hunt about. Or.......

If your clever with electronics you can even knock up a ph-EC-temp-moisture all in one meter/probe using a raspBerry Pi.

loads of blogs about telling you how to make one cheaply.

 

Grtz HC

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Thanks all for the replies.

 

First off, my soil less mixture is premixed, and contains 200g dolomite lime/50l.

It also contains the same amount of dolomite lime, rock phosphate, twice as much 'turbo grow' (rock dusts) and some worm castings. I also usually flush it with pH 5.8 water before using it.

I was watering at a pH of 5.8 and giving very little nutrients (about 1ml/l biogrow), but after a short while of being up-potted (working with clones, the same happens when up-potted to 1.5l pot and then again to 9l) they start to develop what looks like a combination of a phosphorous and potassium deficiency, and possibly magnesium too. I don't know how far the nutes mixed into the medium should go, but the plants are usually slightly smaller than the pot (height and width wise) when the deficiencies appear, which seems too small to me.

 

So I decided to measure the run-off and found it was 7. I decreased the pH to 5.5 but still the deficiencies did not go away, some plants did not recover either.

 

The plants mentioned in the original post also contain a small amount of some organic powdered nutrient with a pH of 7.7, which is why I gave them such a low pH. This nutrient has definitely shown positive results above the standard mix I buy.

Maybe there is too much lime in the mix? I never understood why we buffer the pH towards 7 when the best pH is supposed to be around 5.8, although I do see on here that most people tend to have problems with the pH dropping...

Or maybe I should give more nutrients? I do not see any burnt tips on any of my plants so I don't think over feeding is a problem.

 

Here's a picture of a JB clone, which was perfectly healthy a month previously, but showed a slowing in growth and got these burnt leaves

 

gallery_4870_3080_1067140.jpg

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the mix was probably fine. sounds like the nutrient threw it off. in the future, you can make a solution and water with the nutrient powder and PH adjust the water before applying.

 

you may want to give them some CA/MG, but they are probably oversaturated with nutes. there may be a slight lockout issue, but we'd have to see pics to know. you could flush, but i'd just keep watering with PH adjusted water for a a few days and see if anything changes. you may have some nutrient lockout issues.

 

as for the one in flower, not sure how far along you are, but it appears to be lacking nitrogen, and a bit on the dry side of things. nitrogen deficiency is relatively normal in flowering, and should not be corrected. your PH is probably on the alkaline side. if you just keep watering with properly PH adjusted water, maybe closer to 5 than 6, you should be fine. some leaf damage will not correct itself after the problem is solved. again some CA/MG might help. the slowed growth may imply a flush is in order.

 

the best way to apply nutrients that are overly alkaline or acidic is to make a solution and adjust the PH.

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I believe pH=5.8 is the optimum for hydro setups and chemical fertilizers. In organic grows, pH is much less of a concern, because microorganisms provide nutrients to the roots, in exchange for sugars. Anything between pH 6 and 7 is perfectly fine, so considering your run off it appears your medium is indeed too alkaline.

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As Mostly said......

your working to hydro ph levels not soil.

firstly.......

Here you go.....

untitled.jpg

 

And secondly......

take a look at sannies tabs and bacto as a feed, no need to piss around with ph then....well not till way into flower any way.

Other brands are available but sannies work great. I personally use another brand as I don't have to pay shipping.

 

Grtz HC

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I have been following sannies advice. Add bacto, get the soil life going, do not worry about ph, do not water so much that you have any runoff.

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@Midnight Toker - the results with the nutrient have been better than before, but I have been watering at a lower pH too. Also the nutrient is kinda granular/powder so it would be a hassle to try and water with it.

 

@Mostly Me - Ok, that's good to know :)

 

@Hillcrest - I've thought about buying tabs, but I'd rather seek a local solution too. I'll resort to the tabs eventually if I can't find anything locally.

 

@barney - If I go the Sannie method I'll bear this in mind.

 

A few plants I've got now in veg with the organic fertilizer are doing much better than my previous attempts, and it seems that giving them a low pH is beneficial. I just wanted some opinions from experience on the matter since I didn't feel comfortable giving such a low pH, but I suppose ultimately I must just see how they respond and change things accordingly.

 

Thanks a lot for the advice guys! :)

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What is this granular/powder nutrient ? link please

If not mixed through the soil ...most of these types require mixing with water anyway ......the ones that do neither are a bit shit in my opinion as they rely on a lot of watering to get the nutes to the roots anyway as roots take up nutes in solution..... Not powder.

This feed is sounding odd to me roodni.

this type of feed can lead to high amount of salt build up causing issuses like you are experiencing.

Don't play with your ph .......get it to around 6.5 or there abuts.

Ok....Some strains do like it more acidic or alkaline but as a beginner stick to the 6.5 or just above target or you'll end up loosing out on another grow believe me. Get these basics down. The incorrect ph WILL effect yield and quality

 

Grtz HC

 

Ps....is this nutrient powder made locally or do you mean bought locally? And why are you so into sourcing local ?

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There's definitely something weird going on with the pH and assuming you are getting proper readings from your meter, it has to be the medium or the nutes. In both cases, I'd think about trying something else that is proven to work. It is difficult enough to begin with. At the very least rinse and soak the peat+perlite with/in pH 6,5 water a good 48 hours.

 

For now, that doesn't help. You'll have to stumble in the dark, but the pros here might be able to help you out :)

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Here it is HC http://www.talborne.co.za/index.php?option=com_content&view=article&id=14&Itemid=13

The one I am using is vita fruit and flower.

I am sourcing something local because it is easier and a lot cheaper. It is made here in SA.

So far it is working well, and it was recommended by someone whose opinion I respect.

However, the problem isn't with this fertilizer, it is with the high pH run-off I get from plants with or without the fertilizer (the plant in the pic contained none).

 

It seems odd to me too given what I have read, but I do not feed much nutrients and see no leaf tip burn.

I understand that pH will mess with the plants very well, since I always seem to have a problem with it. My experience with the medium I am using suggests that I need to water at a low pH since I always run into high pH problems. The guy who recommended this product says he waters at a pH of between 4.5 and 5 and his garden is awesome (all organic). I thought I'd ask the question here though, because I am used to reading something different, and after getting a run-off of 6.5 after watering at 4.5 I wanted to hear opinions on watering at a lower pH and what the run-off reading means.

However, I saw the plant I watered at 4.5 respond quite positively, so I think I'm going in the right direction.

I appreciate the input guys :)

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i'm glad it's working out for you... glad your friend has experience with this unconventional method. i've played around with this sort of compensatory effort and it is no fun and a lot of work. it all starts because i make a lazy decision to skip a step or two that ends up being way easier in the end, once it is too late. it teaches us to shoot for precision from the beginning, so we can maintain things, rather than correct or repair them. we may succeed at that correction or repair, but the plant will never entirely forgive or forget in the end, and they will not reward us the way that happy plants will. in other words, you are probably shooting yourself in the foot a bit with yield, flavor, potency, or all 3. no matter how much you balance the water, the plant is still sitting in an alkaline environment. you should probably flush until you get proper readings (assuming you are not already over watering to compensate for PH).

 

i know you can't take the nutes out of your medium, and i am assuming your medium was off to begin with, which is why the nutes can only be throwing it off even more. but in the future, it would be much easier to start with a proper PH of medium, and brew compost tea with your nutes and bacto... this way you will not have to constanly overcompensate for PH problems which will more than likely eventually lead to more PH problems. that PH is liable to eventually lock out nutrients the moment it stops compensating for your extremely alkaline environment. that is why it is a tricky game you are playing. it may be working now, but you may be setting yourself up for more problems in the long run.

 

for now... if you can't or won't flush; at least keep a close eye on the PH going in and the PH coming out. try to do the math if you can. you are watering at about -2 to compensate for about +2 soil. as the window closes, so will your differential. as the runoff PH goes down, raise your PH by the same degree it went down. like if your runoff drops .2, raise your PH water +.2. that's all i can really recommend at this point. without the soil meter, the closest guess you can have is that if you are watering at 4.5 your soil is at about 8.5, assuming you are doing everything right. the runoff is more than likely less than the soil because you are working with mildly soluble granular nutes which are released over time. you are really doing things the hard way. to me it seems like much more work in the long run than mixing granular nutrients into a solution. but since you're in a bit of a jiffy guess it's what is called for. may make you reconsider your approach next time however. ;)

 

best of luck!

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PS: it sounds like your alkaline environment and your plants are eating the acids you are feeding them faster than they can accumulate and affect the soil environment. this could go on a long time before the acids actually balance out the alkalinity. again i would recommend a flush, and more than likely a better acid source. some acids are quickly eaten and some are not as available to plants. citric acid is a good one.

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last thing i swear... this is useful... you can use this in tandem with HC's chart to watch for and identify nute deficiencies caused by PH problems. gives you an idea of why an ideal soil PH is so important.

 

http://www.rollitup.org/marijuana-plant-problems/88003-plant-problems-pic-s.html

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Thank you for your reply MT.

I agree that this isn't the best situation, and hear you on the pH never really being ideal with this alkaline mix, and that it is probably higher than the run-off. I suppose trying to balance everything out like I am isn't the best way...

I don't know why it is the case that this mix is so alkaline, I'll do a bit of research on the organic additives it contains.

 

Ah yes that has helped me a lot, there's a copy of that post on this site too.

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I'm with toker and after reading the very basic info supplied by the link you gave I would say as it's a slow release FErtiliser And looking at the fact your using a non soil mix it's not suitable for what your doing/growing. Being a non soil mix that your using you have little microbe activity to break the fert down. Microbe activity can be found in non soil mixs but it has t be added. Basically it's not a feed your using it should be used IN SOIL prior to planting to help increase nutrients in crap soil sort of...... You have no soil.

imo your problems IS the fertiliser. Go buy a FEED/nutrient range designed for cannabis and follow the schedule that goes with the range and your issues will stop.

 

 

I could be talking crap, I'll leave others to read your link and let's see if others agree....... It think they will. ;)

 

did you not notice its advised to get a consultant to tell you how to use this fertiliser. This you didn't do I know this.

 

If you were a very keen gardener I think you'd be able to use this to a degree. But not as a weekly feed as it simply isn't designed to be used this way.

 

Think we've found your issue.

Have you actually read the info on that site fully ?

feeds are for regular application..... fertilisers are for applying more as one hit wonder so to speak.

(very basic explanation I know)

 

Grtz HC

 

Ps. Once I've sobered up a little in the morning i will re read the info and make sure I'm not talking balls lol

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I'm in no position to argue since I don't have much personal experience on my side (although the few clones I tried this additive with are, so far, clearly happier than those without), but I have seen a great grow report that used this talborne and dolomite lime in pure coco and perlite, with some fish emulsion added every few weeks.

 

That aside, you've failed to note that I said I have just begun to try this fertilizer, and that my problems started way before this, probably due to the alkalinity of my mixture.

 

I've got some biobizz nutes so I'll give their schedule a go sometime.

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Yep I did........ my bad.

still not impressed with the fertiliser though. And I have a feeling that the fertiliser isn't why the grow report was good. Fish emulsion can do wonders on its own.

 

I did say I would re read stuff but I was thrown off my thoughts this morning due to the obvious news.

 

Can we see pics of these clones with and without.

Can you also fully explain your medium mix as you saŷ coco peat/perlite..... Coco I get ....perlite i get......but peat ? Coco isn't peat and perlite isn't peat so are you saying you've added PEAT?

 

Grtz HC

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Hey HC I'm sorry about the late reply, been exceptionally busy and will be for another while. I'll try take some pictures when I can, but as of just before starting this thread I gave the plants that didn't have any talborne a top dressing and they are showing signs of recovery.

My medium is advertised as containing coco peat so I assume that it is a type of coconut fiber based medium.

http://www.hortishop.co.za/promix/ <-- mine is the 'organic promix'.

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