Water Quality Questions

[WaterWitchin]

On a Beginner thread, Stella was asking about pots and watering. Amidst that discussion Roberta replied to a comment I'd made with the following:

You might reconsider for the Paphs, depending on what is causing your high TDS... at the Huntington Botanic Gardens in southern California, they use well water that ranges from 200-800 ppm (unpredictably, more often on the high side of the range) on their world-class Paph collection. In an article in Orchid Digest, Brandon Tam, their orchid specialist, states that they have tried it both ways and the Paphs actually do better with the well water than with RO. Now, the solids in their water are mostly calcium carbonate. If you had high sodium that would be a different story entirely.

I didn't want to hijack Stella's thread, and also didn't think it was necessarily a "beginner" question. Since I grow almost everything in S/H, which may likely make a difference, figured this would be a good place to put my question. I would love to be able to use less R/O water where it isn't necessary.

Last time I looked up my water parameters was about five years ago. It appears TDS has changed a LOT in my neck of the woods over the past five years. No clue why. I also have no idea what amount of sodium, or anything else for that matter, is considered “high.” I’ve put below the latest year of water testing, not bothering with repeating lots of it. If there’s another “thing” I should be looking for, it’s likely listed and I can find it.

I’m hopeful that some of you with much more knowledge than I about science type stuff can give me some sort of rundown analysis on how “good” or “bad” my water is for using less R/O water. For those with the patience and expertise, please help me? Feel free to Bill Nye away, but also something understandable to a non-scientific type such as me would be appreciated within the mix. I’m hoping my buddy Billi-Ray Nye will see and chime in.

And is PPM the same as mg/L, or are those two different measurements?

Calcium 53 PPM
Calcium Hardness (mg/L as CaCO3) 162 variance over year 100 - 170
Chloride 51 PPM variance over year 25 - 200
Iron (mg/L) <0.010 variance over year 0.0 - 0.2
pH 9.4 year average
Magnesium (mg/L) 6.3 variance over year 8 - 26
Manganese (mg/L) 0.0045 variance over year 0.0 - 0.01
Potassium (mg/L) 8.4 variance over year 6 - 12
Silica (mg/L) 9.4 variance over year 5 - 10
Sodium (mg/L) 43 variance over year 20 - 160
Sulfates (mg/L) 97 variance over year 40 - 180
Total Dissolved Solids 320 PPM variance over year 200 - 600
Total Phosphorus (as P) 0.24 PPM variance over year 0.10 - 0.90
Specific Conductance 769 variance over year 404 - 1197 umhos/cm
Total Alkalinity (as CaCO3) 97 variance over year 49 - 145 PPM
Total Hardness (as CaCO3) 182 variance over year 110 - 230 PPM

[wisdomseeker]

The simple... ppm & mg/l are more or less the same ratios commonly used in the water profession for measurement descriptions.

I surely do not want to open a can of worms, so on that note (in my own words): ppm (e.g., basically the ratio of tested parts in a solution that exists at a concentration of one part, per million parts of the solution) *** mg/l (e.g., a liter of water weighs one million milligrams ~ a milligram is 1/1,000th of a gram or 1/1,000,000th of a kilogram).

Staying with 'the can of worms' thing... I'm very familiar with drinking water quality reports because I'm a water professional. I know what is considered to be acceptable for primary & secondary drinking water standards, so I won't comment on the figures in your post pertaining to your water parameters and using it for your orchids (I'll leave that to someone other than me).

I will ask a few questions though. You are using R/O water for your plants now, right? And (don't take these words in the wrong light) *you* know the reasons why you are doing so. Are you mixing your R/O water with your tapwater or are you using 100% R/O water? I surely understand the reasoning of wanting to use less R/O water where it is not necessary.

Again, just an opinion... if it ain't broke, don't fix it... and what works for someone else may not necessarily work for you.

[estación seca]

1000 milligrams (mg) = 1 gram (g)

1000 g = 1kilogram (kg)

(1000 mg / g) x (1000 g / kg) = (1000 x 1000) mg / kg

or 1,000,000 mg in 1 kg

1 milliliter (ml) of water is 1 g

1 liter (l) of water is 1 kg

So 1mg in 1 liter of water represents 1 part out of 1,000,000 or 1 part per million (ppm).

[Ray]

There is never a reason one "must" use RO water, just as there is no reason that your plants must have reasonable humidity or a certain light level. However, ALL orchids can benefit from its use.

Your job is to decide how much you want to pamper your plants.

If you have an RO system, for a typical personal orchid collection - even a very large one - the cost differential of using 100% RO versus blending it with tapwater is relatively insignificant.

The alkalinity and pH of your tap water would be my biggest concern.

[WaterWitchin]

Originally Posted by wisdomseeker

The simple... ppm & mg/l are more or less the same ratios commonly used in the water profession for measurement descriptions.

...

Staying with 'the can of worms' thing... I'm very familiar with drinking water quality reports because I'm a water professional. I know what is considered to be acceptable for primary & secondary drinking water standards, so I won't comment on the figures in your post pertaining to your water parameters and using it for your orchids (I'll leave that to someone other than me).

I will ask a few questions though. You are using R/O water for your plants now, right? And (don't take these words in the wrong light) *you* know the reasons why you are doing so. Are you mixing your R/O water with your tapwater or are you using 100% R/O water? I surely understand the reasoning of wanting to use less R/O water where it is not necessary.

Again, just an opinion... if it ain't broke, don't fix it... and what works for someone else may not necessarily work for you.

Okay, got it I think. PPM and mg/L are the same number. I wasn't understanding why some of the measurements were in PPM and others in mg/L, and thought there might be a difference.

No, I'm not using R/O water for all my plants. I'm using it for paphs, phrags, a psychopsis, a bulbo, where the individual who sold and/or gave them to me (he's a friend) indicated R/O water was a better option. And no, I don't mix R/O with tap water for anything.

Roberta said that paphs were being successfully grown well by Huntington Water Gardens, better than R/O in fact. BUT said the TDS were mostly calcium carbonate, and she didn't know whether my water's TDS were high due to calcium carbonate or sodium. And I don't know, because I don't know what a good or bad range is for either.

So I'm depending on someone who understands water to say things like... oh, you have high calcium low sodium, or the parameters for what's too much calcium, magnesium, sodium, etc. I tried looking through threads, and just got more confused. I'm just trying to figure out what really needs the R/O and what doesn't. I know phrags do.

I'm a pretty smart cookie in some arenas, and in others not so much. I have a learning disability, and the whole chemistry and math stuff cause me to just to blank out and freeze. LOL.... or it could be PTSD from my high school algebra teacher.

I understand one's culture plays a great role in the success or non-success, as does one's environment, etc. Been raising orchids for quite some time. Just trying to get better at it, as we all are.

Thank you very much for your responses.

[Roberta]

Actually, the full name of the institution is Huntington Library, Art Galleries, and Botanical Gardens (The Huntington) The reference with regard to well water vs RO water is in the Orchid Digest vol 84-4, Oct-Nov-Dec 2018, "Paphiopedilum Culture at the Huntington" by Brandon Tam. Just to put in a plug for Orchid Digest, it's an outstanding publication.

[WaterWitchin]

Originally Posted by Roberta

Actually, the full name of the institution is Huntington Library, Art Galleries, and Botanical Gardens (The Huntington) The reference with regard to well water vs RO water is in the Orchid Digest vol 84-4, Oct-Nov-Dec 2018, "Paphiopedilum Culture at the Huntington" by Brandon Tam. Just to put in a plug for Orchid Digest, it's an outstanding publication.

I read what I was able to read without joining. There's no way to see the full paper Tam wrote without joining, correct? Not that I wouldn't love to. Just not in my budget for now.

[Roberta]

Originally Posted by WaterWitchin

I read what I was able to read without joining. There's no way to see the full paper Tam wrote without joining, correct? Not that I wouldn't love to. Just not in my budget for now.

Correct, to get the whole publication you have to subscribe, special issues such as this Paph issue are available individually, but actually cost more than a membership (slightly). Perhaps you know someone in your orchid society who is a member, or maybe the library subscribes. I don't know if Brandon has published comments any place else (he speaks at local orchid clubs a lot, and also travels, making presentations at various conferences, etc.) You can search for his name in society newsletters, many of which are on the web. Or possibly contact him directly. I can share his email address in a PM but would not want to post it for the whole world.

[WaterWitchin]

Originally Posted by Ray

There is never a reason one "must" use RO water, just as there is no reason that your plants must have reasonable humidity or a certain light level. However, ALL orchids can benefit from its use.

Your job is to decide how much you want to pamper your plants.

If you have an RO system, for a typical personal orchid collection - even a very large one - the cost differential of using 100% RO versus blending it with tapwater is relatively insignificant.

The alkalinity and pH of your tap water would be my biggest concern.

Ray, I don't blend. It's either all R/O or none. When Roberta told me about Huntington, it was my understanding the paphs did better with their water than R/O. Thus, my questions. So you're saying my pH and alkalinity are of concern using tap water instead of R/O, right?

I was trying to figure out how much negative effect, if any,from using tap water instead of R/O water for everything. And was hoping someone could tell me something like Well, if your sodium, or total alkalinity or pH is over X amount, it's a real problem. Maybe it can't be explained that easily. I know there are a bajillion genus/species of orchids out there. But I've only got a hundred or so.

I don't mind pampering if the outcome is a big difference; however, I don't want to dump the amount of waste water it would take to make that much R/O water during winter if it's for minimal result. I physically can't salvage the amount of waste water in winter months.

Perhaps I'm not asking my question correctly. Or perhaps it's a question with no easy answer. If so, I'll just carry on. Roberta's comments on paphs just make me stop and think. For me, always a dangerous idea.

---------- Post added at 04:26 PM ---------- Previous post was at 04:21 PM ----------

Originally Posted by Roberta

Correct, to get the whole publication you have to subscribe, special issues such as this Paph issue are available individually, but actually cost more than a membership (slightly). Perhaps you know someone in your orchid society who is a member, or maybe the library subscribes. I don't know if Brandon has published comments any place else (he speaks at local orchid clubs a lot, and also travels, making presentations at various conferences, etc.) You can search for his name in society newsletters, many of which are on the web. Or possibly contact him directly. I can share his email address in a PM but would not want to post it for the whole world.

Okay, that was my take. There is no orchid society within my vicinity. I will attempt to find his writings on the web. And thank you for the offer, but I wouldn't want to bother him for my own personal interest when it's available elsewhere at a cost, or perhaps a synopsis I can find. Thank you.

[estación seca]

If you read my lecture notes here from when Brandon Tam spoke to the Desert Valley Orchid Society (DVOS) you will probably get most of it. I wasn't able to find out what is the pH of his water, however.