Roots and calcium

[Kollba]

Originally Posted by Ray

1) The business about nutrients being best absorbed between a pH of 5.5-6.5 is untrue. Basically, if it is in solution, it is available for uptake and can be. Read this.

2) There is nothing wrong or transient with vinegar as an acidifier. They’re more difficult to find, but I’d use citric or malic acid before an inorganic acid like phosphoric or nitric.

3) Acidifying may change the pH, but it will have no impact on the dissolved minerals in your water. They’re still present and will continue to have the same effect on your plants.

I just looked at some chemistry pages and I suppose the calcium that deposit on roots, leaves, water boilers and so on is calcium carbonate. In contact with vinegar it reacts and give water, carbon dioxide and calcium acetate which can be dissolved in water. So... If I understand my high school chemistry correct... An acidic solution (PH 6,0 - 6.5) of water and vinegar should be able to remove calcium from the roots and stop it from building up new sediment. I am using vinegar to remove calcium from the kitchen sink, the water boiler, the shower head... So why should not a (weak) mix of vinegar and water do the same with plants ?
I might be far out in the blue with my thoughts, but if no one here tells me: "DON'T DO IT!! Because..." I will try it and se what happens...

---------- Post added at 10:43 PM ---------- Previous post was at 10:32 PM ----------

Originally Posted by Orchidtinkerer

The "grey calcium color" of the roots is the same color of 99% of my roots. Roots turn grey when they are dry, it's not a calcium deposit or anything to be worried about, it is their natural colour.

What is more worrysome is that brown scar that looks like a bone joint on the root - a possible sign of an infection but the real thing to be worried about it why the new root tips have died. Yes they are dead so its not the grey roots that are the problem, it is the other roots that have died that are the problem!

There is something wrong with your well water.

I know they turn grey but they are getting more and more grey just in a couple of weeks. And when I water them they are getting less and less green and instead having a grey-green color that does not look healthy in my eyes.

And I am sorry to have to correct you, but the new roots are growing and are not dead. They have been looking like that (brown tip) since they started to grow.

[Roberta]

Remember that the roots are living things, a lot more tender than a shower head or water boiler. If the mix is weak, and washed off quickly, probably OK. For the longer term, do consider vinegar rather than phosphoric acid as your acidifier... you seem to have an enormous amount of calcium in your water... calcium phosphate is very insoluble... I don't know the pH that you need to keep it soluble, but at those levels, you may still be in the pH range where it precipitates. Calcium acetate (which you would get with vinegar) is a lot more soluble. Citric acid (a powder that you'd mix into water) would also work, again because citrates are soluble.

[Kollba]

Originally Posted by Roberta

Remember that the roots are living things, a lot more tender than a shower head or water boiler. If the mix is weak, and washed off quickly, probably OK. For the longer term, do consider vinegar rather than phosphoric acid as your acidifier... you seem to have an enormous amount of calcium in your water... calcium phosphate is very insoluble... I don't know the pH that you need to keep it soluble, but at those levels, you may still be in the pH range where it precipitates. Calcium acetate (which you would get with vinegar) is a lot more soluble. Citric acid (a powder that you'd mix into water) would also work, again because citrates are soluble.

I believe I can go as low as PH 5 (maybe 4.5 ?) without damaging the orchid if I flush it with pure water after. Or maybe it is better to stay at PH 6 and use it every time I water so it will create a long time effect that slowly removes the sediment.
I will try it and see what happens. I can start with a leaf from one of the Calatheas, but first I need to order a PH meter.

[Roberta]

You won't get to pH 5 lr 4.5 with vinegar - it's a weak acid. I think the gradual approach is better. And citric acid might work better than vinegar, it is also a chelating agent. (if you can get it) But definitely, get a pH meter (or test paper) so that you know what you are actually achieving.

[Kollba]

Originally Posted by Roberta

You won't get to pH 5 lr 4.5 with vinegar - it's a weak acid. I think the gradual approach is better. And citric acid might work better than vinegar, it is also a chelating agent. (if you can get it) But definitely, get a pH meter (or test paper) so that you know what you are actually achieving.

It has PH around 3.0 but maybe I need to use a lot of it to reach 4.5.
I bought test paper but it was worthless. I tested it on water, bicarbonate+water and vinegar+water. You could see a small difference in color but not much, so it had nothing to do with the real PH. I will get a PH meter.

[SouthPark]

Originally Posted by Kollba

I am using vinegar to remove calcium from the kitchen sink, the water boiler, the shower head... So why should not a (weak) mix of vinegar and water do the same with plants ?

I might be far out in the blue with my thoughts, but if no one here tells me: "DON'T DO IT!! Because..." I will try it and see what happens...

I would 'recommend' (or suggest only) to NOT do it. Not on orchid roots anyway. It's just a suggestion only, as everybody has choices (and any following consequences from the choices made).

But a few questions are ------ if you have a relatively large number of orchids ---- eg. 300+ orchids, then have you been growing them for a relatively long time? And if so ------ then is this year the first time you've had this 'issue' of grey coloured roots with all your orchids?

And if you have been growing orchids for a fairly long time, then what makes this season different from other ones (in terms of the grey colour)?

Anyway - you could always try it with 1 or 2 orchids to begin with.

For 'safety', it should really be done for a limited number of orchids over a long enough time (eg. a year or couple of years).

I haven't got any orchids with grey coloured roots. So I can't do this test. Will be interesting to learn about the long-term results.

[Ray]

Originally Posted by Kollba

I just looked at some chemistry pages and I suppose the calcium that deposit on roots, leaves, water boilers and so on is calcium carbonate. In contact with vinegar it reacts and give water, carbon dioxide and calcium acetate which can be dissolved in water. So... If I understand my high school chemistry correct... An acidic solution (PH 6,0 - 6.5) of water and vinegar should be able to remove calcium from the roots and stop it from building up new sediment. I am using vinegar to remove calcium from the kitchen sink, the water boiler, the shower head... So why should not a (weak) mix of vinegar and water do the same with plants ?

When you use vinegar to remove the calcium carbonate deposits from hardware, you are dissolving the mineral into a solution, then removing and disposing of it. In the case of orchid roots, the solution is not removed, it is absorbed by the velamen, where the water eventually evaporates, leaving the contained solids behind. The same is true for liquid sprayed on the leaves, only the solids are a thin surface deposit, rather than being absorbed. If you are wiping the leaves with vinegar, it's just like your sink, etc.

Both Calcium carbonate and calcium acetate have one mole of calcium per mole of compound. Vinegar is approximately 5% acetic acid and it takes two moles of acetic acid to completely convert the mole of carbonate into acetate.

If your water has 100 ppm CaCO3, to convert it entirely to C4H6CO4, you'd have to add about 2.4g of vinegar per liter of water, so I suppose that seems doable, but you need to recognize that the true TDS (mass of solute/mass of solution) will increase because calcium acetate is 58% heavier than calcium carbonate.

The only way to ADD something in order to reduce the dissolved solids content is by adding something that causes the solids to precipitate out of the solution.

[Kollba]

Originally Posted by SouthPark

I would 'recommend' (or suggest only) to NOT do it. Not on orchid roots anyway. It's just a suggestion only, as everybody has choices (and any following consequences from the choices made).

But a few questions are ------ if you have a relatively large number of orchids ---- eg. 300+ orchids, then have you been growing them for a relatively long time? And if so ------ then is this year the first time you've had this 'issue' of grey coloured roots with all your orchids?

And if you have been growing orchids for a fairly long time, then what makes this season different from other ones (in terms of the grey colour)?

Anyway - you could always try it with 1 or 2 orchids to begin with.

For 'safety', it should really be done for a limited number of orchids over a long enough time (eg. a year or couple of years).

I haven't got any orchids with grey coloured roots. So I can't do this test. Will be interesting to learn about the long-term results.

I was not going to start with all orchids. I will first test it on Calathea leaves. They dislike low humidity so I spray them with water at the same time as I water the orchids and some of their leaves are getting gray too.

I have not grown orchids for a long time. My wife was taking care of them but she have hundreds of other plants to care for, so they didn't get much attention. And since you cannot have 2 persons caring for water, fertilizer, pesticides without a very strict schedule, I did not touch them. (I have always been a loner and hated working in groups at my job) All of the orchids were potted or in baskets so there were no mounted ones and they only got water 1-2 times a week.
6-7 months ago I decided to take care of them (there were 70-80 orchids) and since I usually go all in, I split some of the old orchids, got some from other people and bought new so there are now 300+ orchids. So... I am still a beginner. (I did the same with with the plants standing under the orchids. Started with none and now they are about 150)

---------- Post added at 08:06 AM ---------- Previous post was at 07:49 AM ----------

Originally Posted by Ray

When you use vinegar to remove the calcium carbonate deposits from hardware, you are dissolving the mineral into a solution, then removing and disposing of it. In the case of orchid roots, the solution is not removed, it is absorbed by the velamen, where the water eventually evaporates, leaving the contained solids behind. The same is true for liquid sprayed on the leaves, only the solids are a thin surface deposit, rather than being absorbed. If you are wiping the leaves with vinegar, it's just like your sink, etc.

The roots will stop absorbing water when they are "full" and the excess water will rinse off the carbon acetate (at least I hope it will). Anyway... Someone has to be the first to try out the idea. I can manage with a few lost leaves on some Calatheas and I will test on just one root on 2-3 orchids.

[Ray]

Originally Posted by Kollba

I was not going to start with all orchids. I will first test it on Calathea leaves. They dislike low humidity so I spray them with water at the same time as I water the orchids and some of their leaves are getting gray too.

Wetting the leaves is not a particularly good way to raise humidity around the plants. In addition to mineral deposits you have seen, it can set the plants up for issues with leaf spotting and various roots.

The idea is to get water into vapor form, and a fogger or evaporation humidifier will be far more effective.

[Kollba]

Originally Posted by Ray

Wetting the leaves is not a particularly good way to raise humidity around the plants. In addition to mineral deposits you have seen, it can set the plants up for issues with leaf spotting and various roots.

The idea is to get water into vapor form, and a fogger or evaporation humidifier will be far more effective.

It is the best I can do because it is outdoors, about 55 sqm (600 square feet), no walls just a shade cloth. The floor will also get wet and add humid to the air for a short while.
I believe it is better than not doing it or am I wrong ?
The leaves dries very fast in this climate, this time of the year.