Acid Injection for Succulents?

[Allen Repashy]

Looking again for anyone with experience here using Acid Injection for PH control. I live in San Diego and our water comes from the Colorado River with a PH of over 8.5 and very high alkalinity... It does work, but is reducing PH worth looking into for better growth response and plant health when it comes to growing out plants from seed?

Any type of Acid over another? Any mixing ratios to share? I would love to hear any points of view on this subject.

Allen

[Tim Harvey]

All minerals are better available for plant use at acidic (i.e. below 7.0) pH. When plants are potted and only receive high pH city water, acidification can produce great results. When plants are grown outside and get rainfall during the year, results are less significant.

I am still waiting to hear of a plant that needs a soil with pH > 7.0

T

[agavegreg]

Not all nutrients are more available at low pH. N and P are absorbed more readily at neutral pH, while K, S Ca, Mg, and Molybdenum are more readily absorbed at a slightly alkaline pH (7-8).

Greg

[Tim Harvey]

I have to disagree. Are you confusing solubility with absorption?

Many cations form insoluble salts at high pH, so unless you are using distilled water, they are simply not in solution at all.

e.g.

http://books.google.com/books?id=1CR...age&q=&f=false

T

[agavegreg]

What do you disagree with. Your chart clearly shows that Ca, MG and Molybdenum are more readily available at a higher pH, and K is available at neutral and high pH with a decrease around pH 8.

According to my Soil Science text by Coyne and Thompson, N, P, K, S, Ca, Mg, Mo, Cu, and B all have reduced availability at low pH. Are they wrong?

I don't think I'm confusing absorption with solubility, the text I use also states that availability of nutrients is generally higher as solubility increases.

I've always felt that it isbest to keep pH near neutral.

Greg

[Allen Repashy]

Hey guys..... great info..... I am on the edge of my seat to learn from your debate here

It sounds like either way it goes, considering acid injection might be worth while considering my PH is always over 8 .. some times of the year it drops to around 8.2, but others it is as high as 8.7....

And then there is the topic of Alkalinity.... or buffer as I know it from years of fish keeping.... it is nearly off the chart here, so attempts to drop PH at all will be met with hard resistance....

Would a low or neutral PH only allow better absorption efficiency that could just be overcome by higher dosing, or can it actually bind some minerals to the point they just can't be absorbed at all or very poorly?

[Tim Harvey]

If they define low pH as below pH 4, then I agree I do not believe anyone advocates keeping soil around pH 4.

However it is clear from an analysis of the data that an acidic solution provides the best overall conditions for nutrient solubility. That was the original question I think. Of course, what happens to the pH once it hits soil is another question.

For implementation, I like Phosgard - it is liquid, acidifies water and is 0-28-25!!

T

[agavegreg]

The chart you linked to shows that availability of N, P and K start to drop as soil pH goes below 6.5-7. For Ca and Mg, availability drops as pH goes below 8.

They even state that "usually the optimum pH is somewhere between 6-7.5 because all plant nutrients are reasonably available in that range."

Granted there are some nutrients such as Fe, Zinc and Manganese that are more readily availbale at low (below 6) pH.

I don't see what the argument is here. All I originally said was that not all nutrients are more readily available when pH is acidic.

[Tim Harvey]

Not really an argument, more a discussion. I certainly favor the pH 6.5 end of things, especially if using city water (usually pH 8) and not acidifying each and every watering.

T

[Matt Maggio]

Allen and others,

Colorado River Water is notoriously high in bicarbonates and carbonates, namely in association with Calcium. Without going into much detail, these are chiefly responsible for the high pH or alkaline condition - which can be a real problem at the levels you're describing. Another concern with these compounds is their tendency to clog irrigation components like low flow emitters. For example, as irrigation water dries around these orifices, insoluble calcium carbonate (lime) will precipitate in deposits. Adding an acid to your irrigation water will help combat this alone.

I would shoot for a pH between 6 and 7. This is the range at which - in most soil conditions - the majority of 17 plant essential nutrients are present in forms usable to plants, and the range in which micronutrients and other metals are least likely to pose toxicity. But even at 7.5, the nutrients most likely to be deficient, N-P-K, are little changed. There is direct toxicity, and reactions with other elements that occur at more extreme pH values. Iron, for example, becomes highly soluble at pH values below 4. This translates to more iron present in solution for reaction with other elements. At low pH, Iron is more likely to form insoluble complexes with phosphorus, making that primary nutrient less available.
At high pH, Ca and Mg does the same with phosphorus.

Buffers are compounds or materials that sponge potential acidity or alkalinity, thereby preventing wild swings in pH. A mineral soil, with some clay present, can act as a good buffer in a growing media.

I would not recommend adding more or less fertilizer to compensate, as this may lead to a host of other nutrient problems and issues with excess soluble salts. Treat the disease and not the symptoms. That being said, there are some acid and base forming fertilizers. Changing the pH with an injection system is easy, as long as you choose equipment that's resistant to acid corrosion. The most common acids used are phosphoric (at Rancho Soledad), urea sulfuric, citric, and acetic(vinegar). I use household vinegar now, but am open to change. The rates will vary by acid and starting pH of your water. Keep adding small doses until you reach the desired pH range.

As far as agaves and aloes are concerned, most should do fine in the 6-7 range, though some of the limestone species could tolerate higher. Most grow on raised slopes where the conditions that lead to severe alkalinity are mitigated. Even field tested soil of Agave utahensis growing in limestone read 7.8. I think calcium availability is most important for these types.

To answer your question on seeds; seedlings will generally tolerate higher acidity than mature plants, and will tolerate fewer soluble salts. Germination could also benefit from fewer soluble salts.

Blah, Blah, Blah...

Matt

[Allen Repashy]

Thanks for the great input everyone....

Another question about how to get the PH down. Is it necessary to inject your acid via a second injector, or can you combine your fertilizer and acid in a single tank and inject it all together. I can see there would be better control using two systems, but if you spent the time to dial it in, is there any potential conflict in acidifying your fertilizer mix.

Also, in an email correspondence with a "successful" it was suggested to add elemental sulfer at an example rate of 2% (I think it is %... the example 10-10-10-2 is how it was valued). which "approximates 8-10% sulfuric acid by volume"

It sounds like a lot of tinkering is in order to really dial in a good combination of PH and NPK. ....

And what about supplementing micronutrients? Is there a prepackaged solution.... what about Iron.... Iron sulfate vs. chelated iron.

I have decided that all of this seems to be of interest to many here and that it will be a great subject to have a round table discussion on at the Agave Summit II....

[iann]

There is no simple rule of thumb for how much acid you need to add to water, it can vary by a factor of a hundred or more depending on the hardness of your water. You can buy test kits which will tell you the total hardness or alkalinity of your water and you could calculate the amount of acid needed to reach a particular pH, but it is simpler just to titrate it. Add some Universal Indicator, then add your acid until the pH reaches about 5. That's how much you will need in future. pH 5 is about what rainwater would be in the absence of other contaminants. Acidifying much less than that would be a waste of time, acidifying much more could damage plants. Watch out for water supplies which vary during the year as water is drawn from different sources. Remember that acidified hard water is not the same as rainwater, distilled water, de-ionised water, or other types of pure water. It will still contain high levels of minerals, just no longer alkaline minerals. You may still get issues with clogging or salt buildup and non-carbonate minerals like iron may still cause problems like staining.

Professionals tend to acidify their water using sulphuric acid. It is relatively cheap, strong, and the by-products are not toxic to plants. It may be difficult to obtain and can also be dangerous, so you might want to use vinegar instead. Phosphoric acid is also an option, but be aware of the extra phosphate that you will be applying.

For semi-permanent modification of soil pH in open ground, elemental sulphur is the only real option. It works very slowly over a period of months to years as it is slowly converted to acid, but is more effective than an equal weight of any other chemical you can apply. It is slowly oxidised by soil bacteria, then hopefully dissolves in soil moisture to produce a reactive acid. Obviously it needs to be applied below the surface in moist soil to be most effective. Again, professionals have used direct injection of sulphuric acid to acidify soil immediately, but without further treatment the soil will almost certainly revert to near its original pH. Sulphur treatment is not suitable for irrigation or use in pots except in very small quantities. In pots you should be using a soil already at a suitable pH.

[Allen Repashy]

Ok, I lost a lot of sleep last night trying to compare Sulphuric acid vs. Phosphoric acid vs Phosphorous acid..... and just when I thought I had come up what I wanted to use.... I found Humic Acid.....

Anyone know much about this and using it for PH control and other potential benefits such as mineral chelating potential and stability. My local fertilizer place carries a product called Humax (12% Humic Acid). It seems like a great option for low organic soil mixes.

Update.........Ok, now I am totally confused.... on the MSDS, it lists the PH as 13..... Isn't an Acid acidic by name?

Allen

[Allen Repashy]

I got on the phone today and Called JHBiotech, and indeed, Humic Acid is not Acidic... leaving me totally confused. I asked him about options for lowering PH and he referred me to their product MixWell Which has B-Hydroxycarballylic Acid as it's active ingredient....

I did a little research trying to figure out what this acid was and the tech sheet reveals the ingredients of it as "L-Ascorbic acid, Vinegar, Water " .....

Meaning it is Vitamin C and Vinegar!...... I wonder about the stability of Ascorbic acid though... Anyone?

[Matt Maggio]

Allen,

I actually think vinegar is Ok, maybe because I just use it with no observed ills and it's on grocery store shelves. Never heard of Ascorbic acid being used in horticulture, and am unsure of its properties.

Humic acids can work as chelating agents for micros and can remove some chlorine from tap water. That pH 13 on the MSDS sounds like a solubility issue, maybe the pH at which the product is fully soluble I don't think they'd make a potent pH adjustor.

Look into Urea Sulfuric acid. The two substances alone can have some problems, but the combination is synergistic and safer to use. It is probably the better choice than phosphoric acid for hard water because of the tendency of calcium to precipitate with phosphates. Even with sulfuric acid, I can foresee some gypsum as a precipitate, but the calcium phosphates are probably worse for clogging. If you choose phosphoric acid, get the white food grade type, not that green stuff. Whatever of these two, you must account for the addition of extra nutrients into fertilizer calculations.

Regards,

Matt

[Kevin Coniff]

Allen,

Check out N-pHuric

[Matt Maggio]

I couldn't remember the trade name, but that is urea sulfuric acid.

[thistlesifter]

Great thread.

I've been developing ideal application for watering. chemistry is not my thing.

I don't have credentials to know or understand the scientific language here. I have several decades experience growing succulents and observing the results using a wide range of techniques.

Successful mass-market wholesale succulent growers with whose operation I am quite familiar inject the least expensive 20-20-20 dissolvable fertilizer they can get. They use the best passive injection system I know of and have used it for many years (over 30). They've had to repair one part 5 times over that period. They irrigate plants situated under 100,000+/- sq ft of plastic. (trying to determine if that makes them professionals - maybe not since they don't use either vinegar or sulfuric acid. ;>)

Here at our little nursery we get a mix of Colo. River effluent with local well water furnished to us by our water supplier. PH varies, never ideal for most stuff.

The practical and simple way for me to look at the water problem starts with the growth medium used to grow roots. I grow roots the best I can. :>) We always think of the roots first.

Assuming there is a porous matrix for the roots to form well and hold-on to, we strive to make it possible for the roots to be exposed to dripping water for no more than 15 minutes per watering with minimum amount of water gloss around the roots after the time limit. Damp okay..water absorbed in the medium to the extent the absorbing medium is glossy when exposed to light => too much absorbtion.

So once the medium meets those qualities. The water problem it reduced to no worries about mineral buildup. Now each watering flushes the root system with a new splash...(would that be considered hydroponic?). I don't know what you call it but it works on those plants that we water by flushing. The timing of the flushes vary by season and is a 'touchy feely' thing.

My way of thinking the ideal root matrix formation cannot be acheived without the medium to support the style of watering that is to be applied. The simplest most generic ways for us to water is by drenching the soil or fogging. (Sometimes the best way to promote root development seems to be by fogging).

We allow:
generic optimum light for the plant
generic optimum air flow through the medium for root development
generic optimum temperature to benefit root development

We specify:
Watering method either flooding or fogging

We Control:
Water chemistry. It is not a generic control.
Three main variants to watering:

Variant 1 Worst case is Use of (as close to) pure water as we can get it (practicable is a good word here and will keep me away for arguments about what 'pure' means). This water is filtered well enough that the most colloidal chemicals are removed (my non-scientific observations is that if sweetened Ice Tea is run through the filter you taste nothing but water in the output especially chlorine in the water used to make the tea).

We add one chemical to the 'pure' water. This water is used for fogging. (Daily - year round except during night-time "open sky" predictions in the winter).

Variant 2 is water company water ammended with liquid acidifier and 2 other liquid chemicals. (Usage of ammendments varies by season and growing periods and is tailored to the crop)

Variant 3. Straight out of the water company pipe to the nursery.

These are selected for use in different crops and all three are used at sometime during the year on all crops.

We are about to purchase a watering system that will allow us to Control our treated water to meet the above requirements.

We will see what happens.


Any pump recommendations?

I've researched them a bit. But am not totally locked-in on one yet.

We've found no perfect one yet, but we are leaning toward an H.E. Anderson system (smallest unit).

Bob Weeks
thistlesifter

[Tim Harvey]

Food for thought Bob ... convoluting it all with growing medium considerations highlights an important aspect so far ignored. I would say that some wholesalers e.g. C & J do grow their plants hydroponically, very successfully too as is well known.

I have to ask what your liquid acidifier for water is?

T

[thistlesifter]

Hi Tim,
the liquid acidifier - generally brown vinegar.

[agavegreg]

Good point about the C&J growing medium. Once I get anything from them over here in Tucson, I immediately get it out of their mix and into my soil mix after trying to remove as much of their mix as possible.

Greg

[Matt Maggio]

I second that Greg. Plants in their mix don't have a good shelf life for reasons explainable.

Matt

[thistlesifter]

Matt,

I kinda agree. "shelf life" may mean different things to different growers.

You can grow in their medium if there is still growing time left in the pot.

Just understand their methods and replicate it. Its an easy thing to do.\

or Move it into another media to match your own regimen.

That is my point exactly. The media puts demands on the chemical styling.

I like the way Tim put it

convoluting it (chemical balance) all with growing medium considerations highlights an important aspect

The feeling of 'grossly overwatering' in a hydroponic setting is the simplest..dumbed-down way to grow succulents. But like many simple things - it works.

Carl and Jim pioneered the development of it in the early-to-mid 1970's and changed everything in the succulent world.

My first visit to C&J's was in 1978...I had only been growing cactii & succulents en masse for 6 years. Nobody I knew quite understood how they were doing it. It turned out it wasn't a secret...just that we didin't know where to get water soluable fertilizer.

Bob

[Tim Harvey]

I can add myself, the Huntington and Miles to the list of those who immediately repot plants from C&J into more conventional mix rather rapidly.

Are their stock plants in the same meduim?

T

[thistlesifter]

Tim,

I don't know if they use different medium for the stock plants.

I will ask one of them next time I see them. Its a darn good question.

B