# Calcium & magnesium supplementation



## Carper (Feb 27, 2016)

Hi All,

I use a general feed, Akerne rain mix, of 13.3.15 with calcium @ 11 & magnesium at 4. My simple question is, are the calcium and magnesium levels sufficient or is it possible to add extra that may benefit the plant? If extra can be added, say in the form of calcium nitrate & magnesium sulphate, how much is safe? 

I feed at a strength no more than around 500 u/S using RO water. I just add the feed until the correct strength is achieved. I adjust the ph normally down from around 6.4 to 5.9.

I normally mix up my main feed to around 300 u/S then around once a month add about 100 u/S of Epsom salts for the magnesium. This does seem to benefit the plants so my thoughts are now turning to added calcium but at safe levels along with the magnesium.

Thanks all

Gary
UK


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## Ray (Feb 27, 2016)

Hi, Gary.

I think you're OK, as-is.

Have you experienced any cases of new growth tips turning black? If so, that is an indication of insufficient calcium.


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## Carper (Feb 27, 2016)

There are a few of these where roots seem to start with good growth then the root tips do turn brown/black and stop! A few of my plants have quite pale yellow leaves which seem to be getting worse. They curl a little around the edges and feel quite thin as though they require something extra! There are no signs of disease etc 

Gary


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## consettbay2003 (Feb 27, 2016)

Carper said:


> There are a few of these where roots seem to start with good growth then the root tips do turn brown/black and stop! A few of my plants have quite pale yellow leaves which seem to be getting worse. They curl a little around the edges and feel quite thin as though they require something extra! There are no signs of disease etc
> 
> Gary



Ammonium sulphate


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## gonewild (Feb 27, 2016)

Carper said:


> There are a few of these where roots seem to start with good growth then the root tips do turn brown/black and stop! A few of my plants have quite pale yellow leaves which seem to be getting worse. They curl a little around the edges and feel quite thin as though they require something extra! There are no signs of disease etc
> 
> Gary



The symptoms you describe fit with ammonium toxicity.
Does the fertilizer contain ammonium nitrogen?


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## Luca69 (Feb 27, 2016)

gonewild said:


> The symptoms you describe fit with ammonium toxicity.
> 
> Does the fertilizer contain ammonium nitrogen?




No, N on Akerne Rain mix is essentially nitrate. It has less than 1% of ammonium. 


Luca


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## Carper (Feb 27, 2016)

gonewild said:


> The symptoms you describe fit with ammonium toxicity.
> Does the fertilizer contain ammonium nitrogen?



No Lance, there is no urea nitrogen source within the feed.

Gary

http://www.akerne-orchids.com/shop/index.php?route=product/category&path=40


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## gonewild (Feb 27, 2016)

What plants are doing poorly? Paphs?

You are adding extra Magnesium but not extra Calcium, correct?

Do you know the pH of your media?


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## Stone (Feb 27, 2016)

Carper said:


> Hi All,
> 
> I use a general feed, Akerne rain mix, of 13.3.15 with calcium @ 11 & magnesium at 4. My simple question is, are the calcium and magnesium levels sufficient or is it possible to add extra that may benefit the plant? If extra can be added, say in the form of calcium nitrate & magnesium sulphate, how much is safe?
> 
> ...



Gary, With your N at 13% and your Ca at 11% you are giving too much Ca already in my opinion - or not enough N. What are the boron levels? The plant just does not need that much Ca. It needs N to make cells so if that is restricted it makes no sense to give it extra Ca which it simply cannot use fast enough. I'm pretty sure that Ca is taken up passively so you really are not going to see deficiencies unless the mix is highly acidic, you are using pure water and you're not adding any to the feed. Very rare that happens.
I noticed that browned off root tips lessened when I increased the N...but not as Calcium nitrate. I use dolomite for most of the Ca and Mg.


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## abax (Feb 27, 2016)

If you can acquire Orchiata and K-Lite in the UK, that should solve any problems with Ca/Mg. I find the two
used together provide excellent nutrition for my Paphs.


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## gego (Feb 28, 2016)

With paphs, I have the same problem when using bark and nitrates. Easy on K with bark, it has enough to supply your plant.


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## Carper (Feb 28, 2016)

gonewild said:


> What plants are doing poorly? Paphs?
> 
> You are adding extra Magnesium but not extra Calcium, correct?
> 
> Do you know the pH of your media?



Lance,

I have tested the PH of the media by passing through RO water in a few of the pots and it is coming out around the 6 - 6.2 range.

Gary


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## Carper (Feb 28, 2016)

Stone said:


> Gary, With your N at 13% and your Ca at 11% you are giving too much Ca already in my opinion - or not enough N. What are the boron levels? The plant just does not need that much Ca. It needs N to make cells so if that is restricted it makes no sense to give it extra Ca which it simply cannot use fast enough. I'm pretty sure that Ca is taken up passively so you really are not going to see deficiencies unless the mix is highly acidic, you are using pure water and you're not adding any to the feed. Very rare that happens.
> I noticed that browned off root tips lessened when I increased the N...but not as Calcium nitrate. I use dolomite for most of the Ca and Mg.



Mike,

The recommended strength for the feed is around 650/700 u/S. I used to feed at these levels but found that the plants seemed to growing just as well at the lower levels. I do lower to around 250/300 u/S through winter due to the british climate. An option may be to increase the feed strength to possibly the recommended levels to increase the N especially as we are approaching spring/summer.

Gary


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## Carper (Feb 28, 2016)

abax said:


> If you can acquire Orchiata and K-Lite in the UK, that should solve any problems with Ca/Mg. I find the two
> used together provide excellent nutrition for my Paphs.



All my plants are in orchiata and I have found it to be the best media for my growing. I have used K-lite and as stated in previous threads I had some poor reactions from plants, ie yellowing of leaves etc so will no longer use it as my plants have now mainly recovered. I may experiment with it again on a few plants in the future but it is not part of my main feeding programme at the moment. 

Gary


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## gonewild (Feb 28, 2016)

Carper said:


> Mike,
> 
> The recommended strength for the feed is around 650/700 u/S. I used to feed at these levels but found that the plants seemed to growing just as well at the lower levels. I do lower to around 250/300 u/S through winter due to the british climate. An option may be to increase the feed strength to possibly the recommended levels to increase the N especially as we are approaching spring/summer.
> 
> Gary



Were the plants that are doing poorly now growing well before you decreased the strength? You can probably see where I am headed with that question. 

The basic MSU formula provides enough calcium assuming the pH is correct so as Ray says a calcium deficiency is not likely. Your pH is not low so that also points away from calcium being the problem.

You said you are adjusting the pH of the fertilizer solution down, what are you using to do that?

The reality is that the MSU studies resulted in a recipe that gave great results. BUT the recipe calls for feeding at a certain strength of nutrients. They came up with that based on the combined ratios of nutrients. Your first move should be to increase the Akrane back to the recommended rate and see if the plants improve.

Dont assume that because people are having good results with using K-lite at very low nutrient levels that you will also get good results at low levels of Akrane. 

Consider also that the few symptomatic plants may have a disease or nematode infestation.


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## Ray (Feb 28, 2016)

gonewild said:


> The reality is that the MSU studies resulted in a recipe that gave great results. BUT the recipe calls for feeding at a certain strength of nutrients. They came up with that based on the combined ratios of nutrients.



Sorry, Lance, but in direct discussions with the developer, I have been told that there was absolutely no scientific basis to their decision to test at 125 ppm N. Quoting directly, "We tried that, and it worked.", but that was at a weekly application rate.


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## Carper (Feb 28, 2016)

gonewild said:


> Were the plants that are doing poorly now growing well before you decreased the strength? You can probably see where I am headed with that question.
> 
> The basic MSU formula provides enough calcium assuming the pH is correct so as Ray says a calcium deficiency is not likely. Your pH is not low so that also points away from calcium being the problem.
> 
> ...



I have been feeding at these lower levels for a couple of years now and looking back, most of the plants seem very healthy. Most are multifloral paphs and species but they do seem to have taken a good couple of years to get to their present stage, when they were nr FS then. We certainly don't get the culture, ie light levels & heat etc in the UK that most others get so I have tried to take precautions in the strength of the feed I give. I will increase the feed to recommended levels & monitor. I use Dyna Gro bloom to lower the PH, which as the Akerne comes out at around 6.2, only takes a few drops, but then to up the PH, I use Dyna Gro Pro-Tekt. When I feed the bloom, which drops the ph to around 4.5 I use the Pro-tekt to bring it back up to around 5.9.

Gary


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## myxodex (Feb 28, 2016)

The problem might not have anything to do with your feeding regime. I would check very carefully for pests and make sure that this issue can be excluded before worrying about nutrient supply.

I grow indoors in the UK and I've had a problem from small slugs living in the medium and eating the root tips. I've seen them in action with a hand lens. Both my paphs and my neos have been affected at different times by these ... and they're small (<= 1 cm), dull gray-brown and so not easy to see. Over the years I've learned that they can come in with new plants. They do not take slug bait and I suspect that they might be a bit of a problem in some EU nurseries.

I've also had thrips and millipedes in my potting medium coincidental with a root termination problem and I suspect these may also cause this problem. The root tips are very vulnerable. It just takes a small amount of damage, maybe even an exploratory nibble from something like a millipede perhaps, to cause infection and terminate a root tip. I wish there was a safe drench to eliminate all medium pests ... if anyone knows ?

From what I've read, calcium is mainly taken up via the root tip and if the root tips are being taken out then a secondary problem could be a calcium limitation (probably other nutrients also) ... but increasing calcium in your feed is not going to help if the primary problem is from pests.


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## Carper (Feb 28, 2016)

myxodex said:


> The problem might not have anything to do with your feeding regime. I would check very carefully for pests and make sure that this issue can be excluded before worrying about nutrient supply.
> 
> I grow indoors in the UK and I've had a problem from small slugs living in the medium and eating the root tips. I've seen them in action with a hand lens. Both my paphs and my neos have been affected at different times by these ... and they're small (<= 1 cm), dull gray-brown and so not easy to see. Over the years I've learned that they can come in with new plants. They do not take slug bait and I suspect that they might be a bit of a problem in some EU nurseries.
> 
> ...



I always strip down the plant and put in fresh medium whenever I purchase any new plant. I check very carefully for pests or any diseases and treat accordingly. Checking my plants on a daily basis, especially as I mainly use clear pots is quite routine and I've not come across any slugs for quite a while. I do think this is down to feeding culture, but it is always good to eliminate all possibilities.

Gary


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## gonewild (Feb 28, 2016)

Ray said:


> Sorry, Lance, but in direct discussions with the developer, I have been told that there was absolutely no scientific basis to their decision to test at 125 ppm N. Quoting directly, "We tried that, and it worked.", but that was at a weekly application rate.



Ray, I don't know why you are sorry?
Many years before MSU published their results scientific trials were done that established the strength liquid fertilizer should be. The work was done at Purdue and UC Davis by a very good friend of mine. When I first saw the MSU formula it appeared to be an exact copy of the nutrients we had been using for years. The rate of 125ppm N is of course approximate but the overall strength of the total solution is the same. And the 125ppm N will give a total of about 600ppm. That rate was found to be very good as constant feed in greenhouse production, actually on the low side. Now if you say the "developer" says they took a wild guess at the rate then maybe they simply used knowledge that was already known, ran some trials and published the results.


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## gonewild (Feb 28, 2016)

Carper said:


> I have been feeding at these lower levels for a couple of years now and looking back, most of the plants seem very healthy. Most are multifloral paphs and species but they do seem to have taken a good couple of years to get to their present stage, when they were nr FS then. We certainly don't get the culture, ie light levels & heat etc in the UK that most others get so I have tried to take precautions in the strength of the feed I give. I will increase the feed to recommended levels & monitor. I use Dyna Gro bloom to lower the PH, which as the Akerne comes out at around 6.2, only takes a few drops, but then to up the PH, I use Dyna Gro Pro-Tekt. When I feed the bloom, which drops the ph to around 4.5 I use the Pro-tekt to bring it back up to around 5.9.
> 
> Gary



How often do you feed the Dyna Grow Bloom?

If it's just a few plants that show poor symptoms then it may not be nutrient related. As I said above consider disease or pathogens that are not visible to the eye.

Or since you are supplying basically no ammonium N, try giving some to the symptomatic plants, If that is the problem you will see fast results.


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## Carper (Feb 28, 2016)

I feed the bloom weekly when plants are in spike and flower and add as an adjuster to lower the ph when required. I will add ammonium N to a few select plants to see the effects. 

Gary


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## gonewild (Feb 28, 2016)

Carper said:


> I feed the bloom weekly when plants are in spike and flower and add as an adjuster to lower the ph when required. I will add ammonium N to a few select plants to see the effects.
> 
> Gary



OK based on that look at phosphorous excess.


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## gonewild (Feb 28, 2016)

Do you feed the bloom in addition the the Akrane or just the bloom?

Do all your plants get it or only those in bud or bloom?

I don't like the concept of high phosphorous bloom boosting fertilizer, so I might try to blame it for your problems.


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## Carper (Feb 28, 2016)

gonewild said:


> Do you feed the bloom in addition the the Akrane or just the bloom?
> 
> Do all your plants get it or only those in bud or bloom?
> 
> I don't like the concept of high phosphorous bloom boosting fertilizer, so I might try to blame it for your problems.



I never used to feed a bloom fertilizer until I tried it about 18 months ago. First I tried it on a few phals. I only used to get a single spike with no branching. Within a couple of months, 3 that I had were in spike & the 4th put out extra flowers. I got between 3 & 4 branches per spike with bigger and more flowers than before. I then introduced this into my regime and on all paphs that have flowered since, there have been more flowers, with better colour & size. I can only base this on my observations. I will only use the bloom feed as an adjustment with the Akerne. I feed the bloom on it's own with plants in spike and the Akerne also on its own to the rest of the collection. The plants in spike will get the Akerne feed about once per month.

Gary


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## gonewild (Feb 28, 2016)

Carper said:


> I never used to feed a bloom fertilizer until I tried it about 18 months ago. First I tried it on a few phals. I only used to get a single spike with no branching. Within a couple of months, 3 that I had were in spike & the 4th put out extra flowers. I got between 3 & 4 branches per spike with bigger and more flowers than before. I then introduced this into my regime and on all paphs that have flowered since, there have been more flowers, with better colour & size. I can only base this on my observations. I will only use the bloom feed as an adjustment with the Akerne. I feed the bloom on it's own with plants in spike and the Akerne also on its own to the rest of the collection. The plants in spike will get the Akerne feed about once per month.
> 
> Gary



Two comments to consider..

Phalaenopsis spikes are induced by cool temperature and not nutrient levels.

Increased flower size, increased flower count and branching are all greatly affected (controlled) by auxins (hormones). Is it possible the Bloom booster has added hormones as well as high phosphorous? 

Increasing phosphorous has been long thought as a way to improve flowering but it has never really proved out in trials. But if it works for you great.
But consider that to increase phosphorous the correct way is to add extraa phosphouros to your normal fertilizer level. That keeps all the other nutrients at the correct level.
When you stop using the Akrane and only use the Bloom what you are actually doing is creating a nitrogen and calcium defiency rather than just a phosphorous increase. And the high level of phosphorous caan quickly prevent the uptake of micro nutrients. Maybe all this does improve flowering but it has all the potential to hinder future vegitive growth at the same time.

Does that make sense?


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## SFLguy (Feb 28, 2016)

Carper said:


> I always strip down the plant and put in fresh medium whenever I purchase any new plant. I check very carefully for pests or any diseases and treat accordingly. Checking my plants on a daily basis, especially as I mainly use clear pots is quite routine and I've not come across any slugs for quite a while. I do think this is down to feeding culture, but it is always good to eliminate all possibilities.
> 
> Gary


Could those small slugs be fungus gnat larvae?


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## gonewild (Feb 28, 2016)

SFLguy said:


> Could those small slugs be fungus gnat larvae?



No. Fungus gnat larvae are much smaller than 1cm.


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## gonewild (Feb 28, 2016)

About bloom booster high phosphorous.
This article about roses explains the problem of excess P.
http://www.rose.org/phosphorus-fallacies-too-much-of-a-good-thing/


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## Stone (Feb 28, 2016)

Carper said:


> Mike,
> 
> The recommended strength for the feed is around 650/700 u/S. I used to feed at these levels but found that the plants seemed to growing just as well at the lower levels. I do lower to around 250/300 u/S through winter due to the british climate. An option may be to increase the feed strength to possibly the recommended levels to increase the N especially as we are approaching spring/summer.
> 
> Gary




If you are going to the N, I would increase the N only (preferably with ammonium nitrate because it is all N - if you can get it (I make my own because you can't buy it here any more) or urea)
to give you double the N you are giving now.

Of course this is assuming good temps and light. (summer) I think you will see a big difference generally by doing something like that.
The main reason to increase the N only is to keep the final EC as low as you can..

To add 100ppm of N from AmmSulph., the EC will be 0.96 (dS/m)..(0.47g/L)

To add 100ppm of N from CalNit., the EC will be 0.84..... (0.84g/L)

To add 100ppm from AmmNit., the EC will be 0.51....(0.29g/L)

0.21 g/L of urea will give 100ppm of N and after it converts to ammonium, the EC will increase by 0.31 d/Sm.

So you can see that using ammonium nitrate or Urea is the best for keeping the salinity lower when supplying extra N.


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## Carper (Feb 29, 2016)

gonewild said:


> Two comments to consider..
> 
> Phalaenopsis spikes are induced by cool temperature and not nutrient levels.
> 
> ...



Thanks Lance, 

It does make sense so I will try and make any necessary adjustments bearing mind what you have said and other comments made by other members. I don't mind admitting that I do find some of the information and calculations a bit difficult to understand as it can very complicated. My experiments are quite simple and I do "gamble" a little based on my "best guesses" but the plants don't seem to suffer and I've been doing this for about 10 years now. Overall, I can't complain with how my collection looks at the moment, but I'm always striving to be better hence the experiments. I've found slippertalk to give me a great deal of information to think about so thanks all for the contributions. 

Thanks all.

Gary


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## Carper (Feb 29, 2016)

Stone said:


> If you are going to the N, I would increase the N only (preferably with ammonium nitrate because it is all N - if you can get it (I make my own because you can't buy it here any more) or urea)
> to give you double the N you are giving now.
> 
> Of course this is assuming good temps and light. (summer) I think you will see a big difference generally by doing something like that.
> ...



Thanks Mike.

I do have some mono-ammonium phosphate if that is any good. What would I need to add in with the akerne feed to up the N?

thanks

Gary


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## gonewild (Feb 29, 2016)

Carper said:


> Thanks Mike.
> 
> I do have some mono-ammonium phosphate if that is any good. What would I need to add in with the akerne feed to up the N?
> 
> ...



You would be adding a lot of phosphorous. 
For each 1ppm of nitrogen you will be adding almost 5ppm of phosphorous.


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## gonewild (Feb 29, 2016)

Carper said:


> Thanks Lance,
> 
> It does make sense so I will try and make any necessary adjustments bearing mind what you have said and other comments made by other members. I don't mind admitting that I do find some of the information and calculations a bit difficult to understand as it can very complicated. My experiments are quite simple and I do "gamble" a little based on my "best guesses" but the plants don't seem to suffer and I've been doing this for about 10 years now. Overall, I can't complain with how my collection looks at the moment, but I'm always striving to be better hence the experiments. I've found slippertalk to give me a great deal of information to think about so thanks all for the contributions.
> 
> ...



Hey I've tried lots of nutrient approaches that did not work out so well. 
Learn from mistakes and successes, remember both and try again.
That's what makes growing plants interesting.


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## Stone (Mar 3, 2016)

Carper said:


> Thanks Mike.
> 
> 
> 
> ...


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## Carper (Mar 5, 2016)

Hi All,

Just a thought about a previous comment I made. I use the Dyna Gro bloom to decrease the PH from the Akerne PH of around 6.4, (at the recommended strength of around 650 u/S).to 5.9. I know this has a large amount of P which could be contributing to a few of my problems. I have increased the feed today to the recommended rates but still wish to lower the PH to my level. I do have some of the K-lite which is 12-1-1. I noticed that the PH at my strength showed a PH of approx. 4.8 in RO water. Would this be a good alternative to use to lower the PH of my main solution. I tried it this morning and I needed 2 litres of K-lite @ 100 PPM N strength solution added to my 40 litres of Akerne 13-3-15. Final reading readings were approx. 680 u/S strength and 5.9 PH.

I don't know whether this makes much sense but your thoughts would be good.

Thanks

Gary
UK


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## phraggy (Mar 5, 2016)

I, like most growers, find these posts very confusing and not easy to understand. I don't go in for' this and that' at certain levels and I certainly would not have the patience. For what it's worth I don't use any labeled orchid feeds.For the last twelve months I use only calcium nitrate, magnesium sulphate and liquid seaweed and it seems to be doing OK for my phrags and multis.
Just to add something. A very notable grower( and I haven't seen better ) uses only phostrogen on all his plants and you should see them!!!!

Ed


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## Happypaphy7 (Mar 5, 2016)

Well, Ed, 

He's got four of the big elements needed by plants. N, Ca, Mg, S.
Then seaweed mix must have the rest in small amount. 
I know that the seaweed bottle only lists K as active ingredient ( at least mine does), but since it came from organic material, I assume it has lots of other things in it.


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## cnycharles (Mar 5, 2016)

If you don't have that much fertilizer to mix up, why not just use lemon juice to lower the ph? Can also use citric acid


Elmer Nj


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## gonewild (Mar 5, 2016)

Carper said:


> Hi All,
> 
> 
> I don't know whether this makes much sense but your thoughts would be good.
> ...



Actually considering you have the K-lite on hand using it is a perfectly fine solution. Using it to lower the pH as you desire will also slightly raises the N ratio
which in effect lowers the P ratio. It is a logical step inline with you nutrient adjustment test.

Using citric acid to lower the pH would also be a good opportunity to see if the citric acid improved growth.... But since you are making a dosage increase of the entire nutrients you would not know if the nutrient increase or citric acid was the cause of improvement or degrade of growth.

Best to make changes in isolated steps if you want to learn what caused a change in growth.


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## Brabantia (Mar 5, 2016)

Carper said:


> Hi All,
> 
> Just a thought about a previous comment I made. I use the Dyna Gro bloom to decrease the PH from the Akerne PH of around 6.4, (at the recommended strength of around 650 u/S).to 5.9.



Strange that you measure a pH of 6.4 with Akerne RM in RO water. This fertiliser is prepared with salts of weak base and strong acid . What is the conductivity of your RO water?
I never found a mineral fertiliser which is giving a so high pH in RO water. Have you checked your pH meter? Using very pure salts I have prepared many fertilysers formulas and always they are giving a pH around 5.6 in pure water (DI water, RO water or rain water). Same thing with AKERNE RM. It is the salts contained in the fertiliser which impose the pH of the solution because all the "pure" water have no buffer capacity.


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## Carper (Mar 5, 2016)

Brabantia said:


> Strange that you measure a pH of 6.4 with Akerne RM in RO water. This fertiliser is prepared with salts of weak base and strong acid . What is the conductivity of your RO water?
> I never found a mineral fertiliser which is giving a so high pH in RO water. Have you checked your pH meter? Using very pure salts I have prepared many fertilysers formulas and always they are giving a pH around 5.6 in pure water (DI water, RO water or rain water). Same thing with AKERNE RM. It is the salts contained in the fertiliser which impose the pH of the solution because all the "pure" water have no buffer capacity.



I have always used RO water and it has always read around the 7.0 ph mark. I often change the filters/units etc. I have only just replaced my PH meter and recalibrated it. I have been using the Akerne now for a good few years and the pH has always been in the range of 6.2-6.4. I can only comment on what I have been doing since first using the Akerne and the new adjustments down to the 5.9 range have been positive.

Gary


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## Ray (Mar 6, 2016)

Gary.

Collect a glass of your RO water, and let it stand out overnight. If you still have a pH of 7.0 the next day, either it's not very pure, so your RO system needs work, or your meter does.

The equilibrium pH of the solution of pure water with the CO2 in the air is about 5.4.


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## naoki (Mar 6, 2016)

Can your ph meter really measure ph of ro water? My typical (lab grade) probe doesn't stabilize. I think ChrisFL explained this in another thread.


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## cnycharles (Mar 6, 2016)

I think cheaper meters would be less moveable in response, and likely show a particular reading like ray is suggesting? I think I got similar readings with my portable meter when I first set up my r/o unit


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## Carper (Mar 7, 2016)

Ray said:


> Gary.
> 
> Collect a glass of your RO water, and let it stand out overnight. If you still have a pH of 7.0 the next day, either it's not very pure, so your RO system needs work, or your meter does.
> 
> The equilibrium pH of the solution of pure water with the CO2 in the air is about 5.4.


 
Ray,

I run off my RO water and let it acclimatise to the temp in the greenhouse for a few days before using it. I measure the temp, Ph and the dissolves solids before and when making up my solution. For about 7 years now I have been carrying out the same routine and the readings have all roughly come out as being PH 7, approx. reading of 4 to 20 u/S and my temp is about 16C. What I have running also are airstones in the water. Even when I purchased a new pen or changed the filters etc the readings have been very close to these. As I have been getting good growth generally over the years and even recently amending the PH down to 5.9, and feeding on what I think is correct, what have I been giving them ?? I have just tested the RO I ran off 3 days ago and it has a reading of 13 u/S and a pH of 7.0! 

My RO unit looks fine at present so a bit unsure where to go next with this.

Gary


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## Ray (Mar 7, 2016)

That would come in somewhere between 5- and 10 ppm solids, so that's OK for a residential system.

Makes me question the meter.


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## Carper (Mar 7, 2016)

Ray said:


> That would come in somewhere between 5- and 10 ppm solids, so that's OK for a residential system.
> 
> Makes me question the meter.



I've used brand new hanna meters and the cheap ones but replace them regularly. All of them have only required a very slight adjustment if any when I used them for the first time. I calibrated them in the usual ph 4 & 7 solutions and the readings given were as I've mentioned previously. My present meter is only a few weeks and seems to be performing Ok.

Gary


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## gego (Mar 7, 2016)

There is a solution recommended to use after using the meter like for storing. Basically you want to start from the same ref every time you use the meter. If you just wash the probe with tap water after using the initial reading will be initially towards the tap water. The RO or rain water may not be able to move that reading. I was advised not use tap and never let the probe go dry with the solution you last measured.

For storage it's best to soak the probe to a certain pH like 4. Then if you want to measure rain or RO, soak that probe first to a ref 7 pH then rinse with RO or rain from a separate container and then measure your RO/rain.

Never let the probe dry up from solutions that have high TDS, salt will build up.
Hope this helps.


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## SlipperMatt (Apr 13, 2016)

I made a little research in the near past, and I would share some info about it. The following datas had been found on Yara's website.
Firstly: Yaraliva Calcinit (calcium nitrate) 15,5N-0P-0K-26CaO Mono fertilizer sufficient dose is 0,05-0,15% solution in horticulture, and possible to use as leaf or normal watering fertilizer also. For orchids i belive, that 0,05% solution is enough, what means in ISO standard: 0,5gr salt /1 liter irrigation water. It means 77ppm N + 95ppm Ca @ every single watering. It should use in vegetative (growing) peroid. It mustn't mix with magnesium sulfate in one stock solution to avoid precipitations.
On the other hand: Yara Krista MgS (magnesium sulfate, epsom salt) 0N-0P-0K-16MgO-32SO3 Mono fertilizer sufficient dose is 0,05-0,1% solution. At 0,05% solution it means: 48ppm Mg + 65ppm S. The preferable watering technique is as leaf fertilizer. It mustn't use in flowering peroid to prevent the flowers against burns. Avoid to spray the leaves at strong daylight or at high temperatures (above 30C degrees).
Suggested methode to alternate the calcium nitrate with magnesium sulfate at every fourth watering cycle, what means 3-4 occasion of both in one growing peroid.

What do you think about this suggestions above for paphiopedilums?
The informations based not my experiences, but i will try it certainly.
I use balanced 20-20-20 NPK + micronutrients fertilizer at half strengt when i fertilize my plants in growing peroid from march to oktober dissolved in 1/3part chilled tap + 2/3 part RO water at pH 5,9-6 in bark mix . Every fourt watering is pour RO. Next i will sprinkle the leaves at every third occasion with calcium-nitrate, and every fourth occasion with epsom salt in dose as above. I would prevent my plants from suffering of Mg and Ca deficiency.
What is your experience/suggestion?

Kind regards:
Matyas


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## troy (Apr 14, 2016)

Leaves can't absorb calcium


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## gonewild (Apr 14, 2016)

troy said:


> Leaves can't absorb calcium



Yes the can.


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## SlipperMatt (Apr 14, 2016)

troy said:


> Leaves can't absorb calcium


Than calcium nitrate supplying with normal watering through the roots as standalone fertilizer once a month, and epsom salt through the leaves will works? And whatabout with quantities and frequency? It looks sufficient?
Matyas


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