Water pH alone has very little impact on coco grow pH

SO whats the solution for tap with high alkalinity? If bringing the pH down won't do anything, how would you keep the coco's pH from rising over time?

It's a worthwhile question.

binaryfission said:

SO whats the solution for tap with high alkalinity? If bringing the pH down won't do anything, how would you keep the coco's pH from rising over time?

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You can try to use that tap water with a fertilizer that has a relatively high percentage of ammoniacal nitrogen.

The only brand of liquid fertilizer that I know of like this is Dyna-Gro.

http://www.dyna-gro.com/

part 3 of Argo's 5 part series: http://www.staugorchidsociety.org/PDF/IPAFertilizers.pdf

i'll check that pdf Carl. Thanks.

I'm in canna Coco. I tested my tap with a Pond kit and my pH is high as well alkalinity. in between 150-300 ppm. So, for now, i will be mixing with filtered water, to retain some alkalinity. The ozarka has very little if any.

I feel this is one of the most important threads i've read. It teaches a concept clearly instead of over-complicating something simple. Carl, must spread. K+

I posted this in the "Good coco grow guide, anyone?" thread and will copy it here.

Most companies that sell coir products advise customers to use the same basic program.

1. Precharge the coir with calcium nitrate or regular nutrient solution
2. Water as the plants need it until roots fully established than water multiple times daily with less volume at each interval for a more uniform wetting profile.

These are not the distributors that we're used to seeing in the hydro stores in the USA. These are probably the companies that Sunleaves, GH, etc. get the coir from.

Links follow

Growing in Coir - www.alternativegardensupplies.co.uk (.pdf)

Galuku Cocopeat Growbags Fact Sheet

BENEFITS OF USING POTTING MIXES CONTAINING COCOPEAT - Galaku Cocopeat

Instructions for the use of coco coir - Performa Globalys (.pdf)

Coco Growbag Support - Millenniumsoils Coir

Growing in Cocopeat - A farmers perspective - Andrew Olley

great thread. reading this a few months back is why is started mixing my RO with tap 50/50.

Im not sure if this has been covered by Carl yet or not, but the pH of water will have a larger affect upon pH of media (and upon water alkalinity) if the pH is very low (ex. < 4) or very high (ex > 11). Sulfuric acid is used in some situations to lower water pH (to low acidity level, ex. ~<4), which in turn lowers media pH and to reduces water alkalinity. In practice this info isn't helpful because we would never want to use water with pH <4 or >11, but for sake of more info, I thought it would be worth adding. I am sorry if this has already been mentioned...

binaryfission said:

SO whats the solution for tap with high alkalinity? If bringing the pH down won't do anything, how would you keep the coco's pH from rising over time?

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There are a few methods one can use to reduce alkalinity of tap water, however, some alkalinity is good, ideally we want 40-60 ppm alkalinity. Over 100 ppm is too high, and over 80 ppm is also in the range I consider too high, but over 100 ppm is definitely too high.

To reduce alkalinity (i.e. remove bicarbonates and carbonates) from water you can pour the water thought plain s.peat moss. That is the easiest method, and cheapest. Another method is to drop the pH very low, ex. ~4, that will lower the alkalinity of water via. neutralization of (some) alkalinity; professional horticulturists sometimes use sulfuric acid for that purpose. But using any pH down should work, it would only mean more would be needed vs. amount of sulfuric acid needed.

RE: soluble ions (ferts) that can affect media pH and level of alkalinity in rhizosphere and soil solution:

Some nitrogen ions, such as ammoniacal N (ex. ammonia and ammonium) are known as 'acidic' nitrogen. This is not due to the pH of the ions, it's due to the affect the ions have upon root and microbial exudates. When roots take in ammonium they release acidic protons (H+ ions), that is why ammonium (i.e. ammoniacal N) is called acidic. The same goes nitrate N, it is called an 'alkaline' (e.g. basic) nitrogen; not because of it's pH but because when roots take in nitrate they exude bicarbonates (i.e. alkaline ions, the same stuff that comprises water alkalinity).

Thus, when we apply soluble ammoniacal N fertilizer we are not lowering water pH or reducing water alkalinity right away (in fertigation tanks/buckets) to any worthwhile degree. It's only when the roots and microbes 'use' the ammoniacal N that said ions reduce rhizosphere and soil solution pH (by virtue of root and microbial exudates), along with reducing level of alkalinity in rhizosphere and soil solution (via. neutralization of said alkalinity in rhizosphere and soil solution). The same goes for nitrates, when roots take in nitrates they will exude alkaline bicarbonates increasing rhizosphere and soil solution pH and increasing alkalinity of said water in media.

yrs, spurr

Spanishwilly said:

Wait, wait, wait.
I'm just reading the exerpt from the dosing handbook. It seems to be saying that from a practical point of view, lowering the PH of an alkaline solution is handled by adding acid.
Lowering the alkalinity however, is accomplished by adding acid.
Additionally, solutions with high alkalinity generally have high PH, ie are alkaline. Is that about right?

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Yup. Water with high alkalinity has a pH of over 7, but water with pH over 7 doesn't necessarily mean high alkalinity.

@ all,

The best and least expensive way to find out the ppm of water alkalinity is to call your source of tap water, for me it's the local governments water purification company. They must regularly test tap water to insure it is within bounders, and they can tell you the ppm of water alkalinity (ppm of bicarbonates and carbonates) and of water hardness too (overall TDS).

The second best way is to send a water sample to a testing lab to get a water analysis that costs (usually) under $50.

We want water alkalinity to be ideally 40-60 ppm, and not over 100 ppm, but keeping it < 80 ppm is safer than keeping it < 100 ppm.

Carl Carlson said:

The R.O. process removes alkalinity.

Match your water quality with the correct nutes.

Use nitrogen content to control pH vis a vis alkalinity in container grows.

edit: I don't know if it was mentioned on this thread already, but the only liquid hydro nutrient that I've found on the market so far that contains a relatively high % of ammoniacal N is Dyna-Gro Grow and Bloom with IIRC 20% ammoniacal N. GH 3 part and FNB / FNG are around 6% ammoniacal N.

FYI

Addressing pH Problems
Fine-tuning your substrate pH is all about the nitrogen. If you control it, you’re in control.

By Matt Taylor and Dieter Lohr
January 2010


Bill Argo is also all over this topic. I posted his links on the previous page.

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I just wanted to point out that although Carl is correct that ammoniacal N (ex. ammonium) can be used to lower media pH and alkalinity (i.e. in rhizosphere and soil solution), using high levels of soluble ammoniacal N with cannabis is probably not a good idea.

Most plants and grasses (such as cannabis) prefer a majority of their N to come from nitrate, not ammoniacal N. And most trees and shrubs prefer a majority of their N to come from ammoniacal N, not nitrate. Tomatoes seem to be at lest one exctpon, they do well with high levels of ammoniacal N in relation to level of nitrates.

The reason using ammoniacal N (like ammonia and ammonium) rich soluble fertilizers might not be a good idea is because ammoniacal N can quickly cause roots to burn. That is, ammoniacal N (like ammonium) becomes phytotoxic to roots (burns them) when the plant is not able to move enough sugar (from photosynthesis) into the roots to convert the ammoniacal N into plant usable forms. When there is a lack of sugar, or the uptake of ammoniacal N outpaces movement of sugar into roots, phytotoxicity sets in.

Using a fertilizer with 20% ammoniacal N would not be a good idea IMO, esp. considering it would only be to reduce media pH and alkalinity, which can be accomplished in other ways (such as reducing the amount of nitrate N used; not in terms of relation to ammoniacal N).

There are many tomato specific all-in-one fertilizers that have higher levels of ammoniacal N than nitrate N, and probably cheaper than Dyna-Gro. That said, the easiest way to increase ammonium in fertilizer water when also using cannabis-style fertilizers is to apply ammonium sulfate or monoammonium-phosphate (MAP) as an 'extra' fertilizer to the mix. This way a grower could reduce the ratio of Nitrate-N:Ammoniacal-N, and not provide too much ammoniacal-N. An ex. of too much ammoniacal N, IMO, is a ratio of less than 10:1 nitrate:ammoniacal N, and esp. if more ammoniacal N is present than nitrate N.

Nitrate fertilizers are usually provided via. calcium-nitrate, and nitrate N causes roots to exude bicarbonate (alkaline) ions when roots take in nitrates. That causes an increase in pH and alkalinity of media pH (rhizosphere + soil solution). Thus, if we simply reduced the ppm of nitrate we would in effect be reducing the pH in media by reducing the buffering ability of alkalinity (by reducing alkalinity, that which comes from roots) and by directly reducing increase of pH by reducing the release of alkaline ions by roots.

The other problem with providing a lot of ammoniacal N, besides the greater risk of burning roots, is that ammoniacal N reduces uptake of nitrate by roots after a few hours. I believe the reason is when roots take in and convert the ammoniacal N (mostly into amino acids) those amino acids build up in the phloem. When a level of some amino acids is reached in the phloem the plant will self-regulate uptake of nitrates, thereby reducing uptake of nitrates. Plants can't self-limit uptake of ammoniacal N (which is why ammoniacal N can burn roots easily) but plants can and do self-limit uptake of nitrates.

Roots take in, and use (convert) ammoniacal N faster than nitrate N. So if a fresh hydro rez is mixed with 100 ppm ammonium and 100 ppm nitrate, the ammonium would be used faster and to a greater degree than nitrate.

IMO the best way to increase ammoniacal N in media is not by adding soluble ammoniacal N because that can cause problems as I described above. The best way would be to apply limited quantities of blood meal because as it is mineraized my microbes (both bacteria and fungi) ammoniacal N is released (as ammonia and then ammonium). Even in chem fed coco there will be microbes that can breakdown blood meal. Thus providing slower-released source of ammoniacal N vs. the blast of soluble ammoniacal N that comes from application of soluble ammoniacal N ions.

just my 2 cents...

What if you are using tap water that is 173 TDS, Hardness of 152 CaCO3 mg/L, 35.8 Ca mg/L, 11.6 Mg mg/L, and a 7.4 Ph?

I asked this question in another thread. I dont PH the water...ever. Would you see issues right away with this water or not?

Now I dont use coco but instead a peat based soil (LC's).

there is a great difference in peat based soil and coco, when it comes to peat based soil i would say it would take time before there will be issues - but im not a soil growing expert, although i defend my self pretty well in the garden outside

the ph of soil is much more dificult to affect than coco. in coco in a few waterings the coco's ph starts rising.

using canna nutes one can be sure the ph of the nute mix will be good, if the water used for mixing has a ec of less than 0.5 - the nute mix will be around 5.8-6.0 ph. this is because of the humic and fulvic acids used in the nutes, and also because of other acidic components.

also in profesional agricultural hydroponic setups using coco for growing various vegetables, the ph is allways adjusted for maximum efficiancy in nutrient uptake and control.

ph greatly helps to controll the nutricion uptake by means of accesabillity for the roots to certain minerals.

this means its possible in most hydroponic cultures of peppers for example, to guide very preciselly new growth and continuos fruiting.

in marijuana the fruiting is not continous as in some veggies, so here the main objective will be to keep the ph around the best nutrient range suited to the growth of the moment. there is various sources of information about this and its easilly accessible on the internet - so go have a search and read a bit.

plants are little complex producers that can be controlled and tailored into grow in various ways and in many conditions. there is even tests with using saline water, and sulfuric acid to neutralize the salinity and as far as i have read the results are surprisingly good. it is obvious this is giving great hopes for poor areas where culture has not been possible by tradicional means because of high salinity of the ground water.

still coco same as soil aloves for many methods of cultivation - some will be more productive than others - but many will work ok..

peace

Ok guys I went out and bought a Bluelab EC Truncheon and an aquacheck pond kit at Lowe's. The truncheon is lighting up in between .2-.4 EC, 100-200 on the ppm(ecx500), and 140-280(ecx700). The pond kit read in between 40-80ppm alkalinity. PH is at 7.7. So is my tap good? I was thinking about running Ionic(hardwater), Maxibloom with my tap just to see how things go. I'm hating to waste all the water running my RO. Thanks!


D2G

Carl Carlson said:

You can try to use that tap water with a fertilizer that has a relatively high percentage of ammoniacal nitrogen.

The only brand of liquid fertilizer that I know of like this is Dyna-Gro.

http://www.dyna-gro.com/

part 3 of Argo's 5 part series: http://www.staugorchidsociety.org/PDF/IPAFertilizers.pdf

The “best” fertilizer to use on your plants is the one that not only supplies nutrients, but also complements the alkalinity and nutrient content of your irrigation water. In this article, we will help you understand how selecting a fertilizer will affect the pH and nutrient levels in the substrate. You will learn why water-soluble fertilizers are classified as acidic, neutral, or basic based on their fertilizer reaction in the substrate. Finally, with the information given in this article, you should be able to decide for yourself which fertilizers will work best for your growing conditions.
​

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A natural fertilizer such as stale urine maybe?