I'd like to discuss stagnant water

[abax]

and Phrags. Common definitions of stagnant water generally mention water that isn't moving. Obvious,
right? What are the specific properties that makes water
stagnant...low oxygen? Bacteria accumulation? Since it
seems important to supply fresh water often to Phrags.,
I'd like some specific reasons why. What, for instance, does
fresh rain water have that "stagnant" water does not? ST
has some excellent scientific minds and I'd like a little
expansion on this subject.

 

[John M]

Stagnant water is simply water that is not flowing, or moving.....= Standing water. This in itself is not a bad thing for our water loving Phrags, except when the lack of movement and mixing of the water with the air, prevents oxygen from being disolved into it at an equal or greater rate than the bacteria in the water that are consuming the organic particles use up the available oxygen. When the oxygen is depleted, not only do the plant roots that are in the water become starved for oxygen; but, the bacteria population in the water becomes more of the anaerobic type. This type of bacteria often produce toxic gases which are disolved into the water, putrifying it, making it smell bad and becoming generally quite poisonous to most life. Solve this problem by frequently flushing out shallow trays of standing water that you may have your Phrags in, with fresh water.

Fresh rain water has ample oxygen = good! Rain water that has collected in a depression, or a containter, or has been poured into a shallow tray is considered stagnant if it's not moving and interacting/mixing with the atmosphere. After a time, when all the oxygen is depleted...and if there is any organic matter in it (rain does have tiny amounts of organic matter, despite being naturally soft and largely mineral free), that organic matter will begin to putrify. It doesn't matter the source of the water (rain, tap, etc.), if it stands and is not moving, it's stagnant and if it does this long enough and it contains organic matter, it will become putrified.

 

[NYEric]

Don't even deal with it. I have my Phrags in trays with little aquarium pumps to keep the water moving.

 

[monocotman]

stagnant water

Another thought.
I don't bother with this issue at all. My plants sit in about 1cm of 'stagnant' water year round and are never bothered by it. I just replenish the water by watering the plants when the level drops, about once a week, more in summer.
The water has a huge surface area to volume ratio as it is so shallow so oxygen depletion is not a problem.
David

 

[gonewild]

Beyond the simple definition of the word...

When water is referred to as stagnant it is more that just water that does not have a current. Stagnant water along with being without a current also has content that makes it unattractive such as a foul order, bad taste or just plain ugly in appearance.

A motionless pool of water that is crystal clear would be described as fresh.
A pool of water that has scum on the surface and smells sour would be called stagnant whether it has a slight current or not.

If you are told or read not to use stagnant water the reference is to the contamination in the water, not the fact that it has no movement. Stagnant water has some undesirable content that is best avoided.

 

[John M]

I agree with the others. The very few plants that I do stand in "stagnant" water, are not a worry to me because I replenish (therefore, refresh with well oxygenated water), the water before it has enough time to become contaminated with anything undesirebable. Also, because I don't irrigate my plants with "dirty" water (high in organic matter), it takes such a long time for standing water to "go bad" that it would evaporate before putrification had a chance to happen.

I agree with Lance, insofar as the common usage of the word "stagnant". However, I answered your question literally, not based on the common (and incorrect), usage. Most people refer to "stagnant" water as a bad thing; but, water that is only stagnant is not necessarily bad at all. However, the status of being stagnant, highly favours the development of contamination, which is harmful.

However, the blanket statement "Stagnant water has some undesirable content that is best avoided", is not technically correct. Being stagnant is in and of itself, not a bad thing. "Stagnant" = "standing"...that is: water that is not moving and therefore, not offgassing harmful gases and not absorbing oxygen from the atmosphere. However, if you start with clean, clear, well oxygenated water, pour it into a tray and it is not moving, technically, it is stagnant. If you leave it for long enough, it will become contaminated over time if there is organic matter in it to begin with, or if organic matter (dust, soil, vegetable matter, dead insects, etc.), falls into it over time. Being stagnant can easily and quickly lead to being a bad thing, under the right conditions. It all depends on the organic impurities in the water, the bacterial count, the rate of contamination by organic matter from the surroundings and the temperature. A "motionless pool of water that is crystal clear"...is often described as fresh; but technically, the correct description is that it is "stagnant fresh water", as opposed to "putrid fresh water".

Stagnant is a term to descrive the physical properties of the water (not moving). It does not describe the content of the water (impurities, contamination, toxic disolved gases, etc.). However, the confusion arrises from the fact that stagnant water often does "go bad" and become contaminated. Whereas water that is moving vigorously and able to offgas the toxic gases (produced by the breakdown of any organic matter) and absorb oxygen (which keeps the good type of bacteria alive), will remain healthy and not be considered as contaminated, or bad. "Stagnant", does not directly describe the impurities of the water, they are a consequence of the water being stagnant, allowing other processes to take place. Impurities are not the basis of the definition of the word "stagnant".

 

[gonewild]

Not trying to argue but if you are talking about the water quality and how it affects plant health then stagnant refers to contamination and not motion.

Under the strict limited definition of "stagnant" a glass of fresh rain water is stagnant. But I don't think that is the "stagnant" water the question is about.

 

[Ma_sha1]

My phrag usually stands in up to 1" of stagnant water, gets changed 2x a wk. raised it to 2" for a 8 day trip & it got a bit stinky and minor rot



Sent from my iPhone using Tapatalk

 

[cnycharles]

quite a discussion! May have slightly different definitions or usage depending on which version of English you are used to. Water can be recently not moving, or even moderately long not moving and gets called 'standing' water. Also can be called pooling or pooled water. After a who knows how long period of time if the water starts to 'decay' in the manners very well described here it becomes stagnant. I think it's usually a quality thing since you can have bogs with water that doesn't move out through a discharge but it may not qualify as stagnant in quality. If there are plants filtering or refreshing the water or some is periodically moving in in may not quite become stagnant


Elmer Nj

 

[Clark]

I use dunks.

https://www.homedepot.ca/en/home/p.mosquito-dunks---2-pack.1000700324.html


All good.

 

[John M]

Not trying to argue but if you are talking about the water quality and how it affects plant health then stagnant refers to contamination and not motion.
Then "stagnant" is incorretly used to refer to "...contamination...". We all, including myself, often gratuitously give the term "stagnant" a negative conotation, especially when it comes to us drinking stagnant water, using it for raising fish and using it to water our plants. We use "stagnant" (incorrectly), to describe unpleasant, contaminated water, when actually the terms "stagnant" and "standing" can be freely interchanged without changing the meaning of a sentence and they have nothing to do with water quality....although, they both can easily lead to a given body of water becoming contaminated and unpleasant/unhealthy. If you are refering to contamination, then, while it may be true that stagnation might have contributed to that condition, it does not describe that condition, nor does it mean that the condition actually exists in a given body of water. "Stagnant" means only stagnant, nothing more. Stagnant water is water that is not moving...nothing more.

It is clear that Angela already knows that stagnant water is water that is not moving; but, she was seeking opinions about further specifics of that definition, if there are any, of which there are not. If she'd used some adjectives and asked about "old stagnant water", or "dirty or cloudy stagnant water", or "smelly stagnant water" my reply would've been more in line with what you're saying.

However, Angela didn't ask about that. She said:
What are the specific properties that makes water
stagnant...low oxygen? Bacteria accumulation? Since it
seems important to supply fresh water often to Phrags.,
I'd like some specific reasons why. What, for instance, does
fresh rain water have that "stagnant" water does not? ST
has some excellent scientific minds and I'd like a little
expansion on this subject.

To answer her questions: The specific properties that makes water stagnant is that it is not moving, not it's oxygen content, or bacterial count. However, stagnation can lead, over time, to low oxygen and the accumulation of toxin producing, anaerobic bacteria, which is not a good thing. Therefore, it's best to avoid long term stagnation of the water that you would use on your plants.

It's important to supply lots of fresh water to Phrags because many of them grow along streamsides and on wet, rock seepages where the water has good contact with the atmosphere and is therefore well saturated with oxygen. Also, the continuous movment of water past the plant's roots, prevents the accumulation of disolved salts (which happens when there is evaporation), which Phrags do not like. Plus, Phrags that grow in these wet environments are receiving water that has accumulated from heavy rainfall and/or, glacier melt, making it naturally pure and low in minerals, giving us a clue about how to grow our Phrags in cultivation....eg. lots of low mineral, highly oxygenated, fresh water.

Fresh rain water can be stagnant if it has pooled and is no longer moving. At first, this stagnant rain water will contain lots of Oxygen and be very good for your plants. in time, this stagnant rain water will lose Oxygen and begin heading towards being "sour", a condition that really means that the organic matter in the water has rotted to the point that the bacteria which are breaking down the organic matter have used up all the oxygen. Now, you have an anaerobic condition and the Oxygen loving bacteria die off and are replaced by anaerobic bacteria, which do nasty things to the water. If you are refering to stagnant water that has had time to go "off", the answer to the question (What, for instance, does
fresh rain water have that "stagnant" water does not?), is: Mainly Oxygen. It all comes down to the direct and indirect harmfull effects of low Oxygen. Just keep the water well Oxygenated (moving, not stagnant), and the plants will be happy, assuming that your water source is a good, healthy one to begin with.

Under the strict limited definition of "stagnant" a glass of fresh rain water is stagnant. But I don't think that is the "stagnant" water the question is about.You're assuming things about Angela's inquiry, not in evidence. I think the knowledge she was seeking was at the very basic level....a good place to begin when trying to learn and understand a concept. Because it was not clearly and completly spelled out what exactly Angela wanted to know, I felt it was best to start at the beginning with the correct definition of the word in question (stagnant) and go from there. What you're talking about is the potential, or even the likely result of water being stagnant, over time; but, not the condition of water being stagnant and what that means. It's not clear that what Angela wants to learn about is contaminated, smelly, "bad" water, or if she simply wants to learn about water that is standing....aka, "stagnant".

The Oxford Dictionary of Current English: "...(of liquid) motionless, having no current; showing no actrivity, dull, sluggish;..." Anything beyond that definition is playing fast and loose with the definition. The result of prolonged stagnation can be what you're talking about; but, it does not have to be in every case. What you're talking about, although important and practical information, is not part of the definition of stagnant, it is the (frequent), result of being stagnant.

..

 

[gonewild]

From Cambridge dictionary, they add an addition to the definition "smelling unplesant", which adds something besides motion in the form of contamination....

stagnant

adjective uk /ˈstæɡ.nənt/ us /ˈstæɡ.nənt/

stagnant adjective (NOT FLOWING)

› (of water or air) not flowing or moving, and smelling unpleasant:
a stagnant pond

 

[gonewild]

What, for instance, does
fresh rain water have that "stagnant" water does not?

Stagnant water has a lot more in it than does fresh rainwater.

Fresh rainwater basically does not have anything in it. It likely would have more beneficial gases like O2 and CO2, but the direct benefit of them is not really much when dissolved in water. It probably would not have any harmful bacteria or pathogens living in it.

Stagnant water (dirty, smelly) would be low in O2 and CO2. It probably would have a higher pH than rainwater. It may very well have toxic gasses that get released such as methane, ethylene, and others. Stagnant water can easily harbor populations of bacteria that cause leaf or root diseases. Fungi spores also collect in and can be spread by stagnant water.

Stagnant water may also have good stuff in it that benefits plants like nutrients but that benefit is negated because we use fertilizer.

 

[abax]

I think my question has been answered very well. I renew
the water in my saucers every two to three days on average. Sometimes with rain water out of my gallon jugs and sometimes tap water. Our tap water is very good and doesn't seem to have detrimental effects on
even species Phrags. For instance, my besseae are my
very best growers and bloomers. Often we assume common terms that we throw around have a different
connotation than the scientific explanation, the why of
something. My 55 gal. rain barrel is covered with both
netting and a solid top and is renewed every time it rains...which is ALL the time here. I suppose it could be
described as "stagnant", but I constantly check it for
smell and ph on a weekly basis for just my own curiosity.
I think it's a good thing to discuss common terms on
occasion for clarification. Again, thank you John and
Lance.

Eric, I have my Phrags. in individual saucers because I have the room to do so. However, the bubble stones
are a really good idea for communally grown plants sharing containers. I can just dump out saucers on the
greenhouse floor...quite a luxury really.

 

[Hien]

if the problem is lack of oxygen , can we just add a little bit of Hydrogen peroxide into the water for the plants ?
Hydrogen peroxide degrades into water & oxygen , would that provide the plants with water with higher amount of oxygen than normal?

 

[John M]

Well, it seems that there is room for interpretation, Lance. Odd though, that you use the Cambridge definition for "stagnant" in British English, and not the Cambridge definition for "stagnant" in American English. According to Cambridge, in American English, the definition is this:

"stagnant" in American English

stagnant adjective (NOT FLOWING) › (of liquids or air) not flowing or moving, and often smelling unpleasant: Hot, stagnant air filled the subway

The use of the word "often" in the American English definition tells us that sometimes, there is no unpleasant smell; but, by definition, it is still "stagnant". Therefore, smelling unpleasant is not a critical requirement to the definition. "Smelling unpleasant" is a common consequence or development of (first), becoming stagnant. Smelling unpleasant is not a requirement to be considered as stagnant. This brings us back to my point that water can rightly be considered stagnant without yet having reached a point of becoming unpleasant smelling or contaminated in any way.....because, while being unpleasant smelling and contaminated is often the result, or consequence of prolonged stagnation, it is not a part of the obligatory definition of "stagnant".

Anyway, it hardly matters now. There are different interpretations and I think Angela has enough information to consider the pros and cons and make a wise decision about how she'll grow her Phrags.

We're both wrong and we're both right, at the same time. We're each entitled to our right to choose which definition we will favour. I choose the simpler, cleaner definition of "stagnant" because to me, that is the most accurately informative. If I want to further describe stagnant water that has an unpleasant odour, or other property, I'll add more specific adjectives to accurately describe the condition of the water. I'd rather not use the more broad sweeping definition that all stagnant water must have "something" wrong with it, without being specific about what that "something" is. For example: If I'm describing water that is standing and therefore, at risk of eventually becoming Oxygen depleted, I'll simply call it "stagnant water". If I'm describing water that has been standing for a very long time, I would assume that it likely will have low Oxygen levels and I'd call it "Oxygen depleted, stagnant water". I'll call water that has a bad smell "Putrid, stagnant water", etc.

Angela, the bottom line is do whatever it takes to ensure that your irrigation water is well Oxygenated. Either use up stored water quickly; or, for prolonged storage, use a pump to circulate stored water, or use a bubbler. The thing is to get the water at the bottom to rise up to the surface and come into contact with the atmosphere, where it can pick up more Oxygen. Well Oxygenated water is good for plants. Water that has been stagnant for awhile is not well Oxygenated and therefore, not as good for plants....and as Lance has pointed out, old, Oxygen depleted, toxin laced, stagant water can be downright unhealthy for plants.

 

[John M]

if the problem is lack of oxygen , can we just add a little bit of Hydrogen peroxide into the water for the plants ?
Hydrogen peroxide degrades into water & oxygen , would that provide the plants with water with higher amount of oxygen than normal?

I believe that adding Hydrogen Peroxide does as you say and it increases the Oxygen level in the water. However, how long this lasts, I don't know. It's probably highly variable. Also, is there a likelyhood that to keep water well Oxygenated by using H2O2, you'd spend a lot of time testing the water and physically adding the H2O2.....and wouldn't you end up spending a fortune on H2O2? I bet adding H2O2 is a lot less practical and a lot more expensive than to simply keep the water moving vigorously with a bubbler or a small pump, so that it has lots of active contact with the atmosphere, where it will naturally and efficiently pick up plenty of Oxygen.

 

[gonewild]

Well, it seems that there is room for interpretation, Lance. Odd though, that you use the Cambridge definition for "stagnant" in British English, and not the Cambridge definition for "stagnant" in American English.

:rollhappy: I did not choose the specific dictionary, it sort of choose me! I googled the phrase "stagnant water" rather than just the word stagnant. That way I could see the subject defined rather than the isolated word. The Cambridge dictionary was just one of the random choices.

Obviously I don't disagree with your interpretation because it is not incorrect.
I come from the American West and the word stagnant is used as a description of water quality, as in fit to drink or support healthy fish. A slow flowing stream of smelly water and full of scum would be called stagnant water even though it is in motion. Water motion would be described as flowing or not flowing. Water quality is fresh or stagnant, Actually most old ranchers refer to fresh clean water as "sweet" and that has nothing to do with sugar!

 

[cnycharles]

There is commercial peroxide, both food grade and not that is mixed with water using a preset injector and applied to either leaves or root zone to raise the oxygen level and/or somewhat disinfect the soil. It is temporary but does work


Elmer Nj

 

[mrhappyrotter]

I don't want to get into a debate over definitions and semantics, other than to point out that definitions of words change in meaning over time (i.e. consider the word decimate) and in different contexts.

That aside, in this context, I don't necessarily think stagnant is totally synonymous with standing water. If the water in a phrag's saucer is cloudy, smells putrid, or has formed a significant film on top, then I consider it to be stagnant and take steps to fix that immediately.

If the lip of your saucers have a significant gap between them and the pot, and the water is relatively shallow, this allows quite a bit of surface area on the standing water, which helps keep the water fresh, clear, and decidedly non-stagnant. My plants have never shown any issues when left to stand in the same water for days (sometimes longer) at a time.

Even so, unless I'm in a big hurry when I water, I empty the old water out and replace it with fresh water. My "fresh" water though is often rain or RO water that's been sitting in milk jugs or other water containers, and possibly doesn't have the most dissolved oxygen, but which still follows the same criteria listed above -- water is clear, no putrid odor, and minimal if any film. I think the process of watering ultimately ends up oxygenating the water. I gets poured into a dish soap bottle, squirted into the pot, slides through the chunky media, and then collects in a wide shallow pot.

Also, think about semi-hydroponic setups. SH is basically the ultimate stagnant water growing method, so to speak. The water in the reservoir has restricted direct exposure to moving air, and yet phrags love it.

So, I guess what I'm getting at is, as long as you're not seeing the warning signs that the water has become a bacterial soup, then it's not really something to worry much about. I'm sure the plants would be very slightly happier if you were watering them with fresh, clean, new water several times a day, but that's a lot of time and effort with a diminishing return in terms of overall plant health.

Just my opinion / growing philosophy of course, others may disagree.

And, anecdotally, I have lots of fish tanks with no air stone and no running filters on them. They're basically just standing water. They support lots of fish, shrimp, snails, and more. The oxygen in these tanks is entirely supplied via whatever dissolves from the surface. These are 1 - 10 gallon tanks. I guess my point is, having sufficient surface area alone is plenty to keep oxygen levels up in a saucer. Just keep the plants and saucers wet at all times and keep your feeding rates low but consistent, you get a good stable bacterial ecosystem that tends not to get out of hand, and keeps the oxygen hogging bad stuff at bay.