Stone
Well-Known Member
I'm surprized by that. One of our club members took the same readings in an Ecuadorian Odontoglossum habitat (cloud forest again) and got a reading of pH 4 off the dripping moss.
K-Lite has been around a few years now... updates?
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I'm surprized by that. One of our club members took the same readings in an Ecuadorian Odontoglossum habitat (cloud forest again) and got a reading of pH 4 off the dripping moss.
ehanes7612
Well-Known Member
I used to grow in CHC and fertilizer with higher K than K lite..can't remember the name of it or the ratio. Great for seedlings out of flask but terrible for adults and seedlings two years and older. I switched to K-lite and repotted everything in bark/perlite/sphagnum. I noticed a remarkable improvement in new growths but wasn't sure why, yet I was still getting premature yellowing in mature growths. That was in the greenhouse. Last summer I moved everything back under lights (1000 watts/12 hours and four to six feet away) and since I didn't want to humidify beyond natural humidity , I made my mix more porous (also subbed rockwool for sphagnum) knowing I was going to water more often. I only grow multi paphs and phrags from deflasking to adults now and everything is growing great. For the first time, I am getting that nice shiny coat to the multifloral leaves (perhaps due to the low humidity/higher frequency in watering) and every succeeding growth is a healthy green. I water every other day, use k-lite once every two weeks for two waterings in a row at suggested strengths. My temps are constant 85-88 day and 60-63 night. I agree with Tom in that orchids have many ways at adapting but most of all they just want consistency. My plants get everything on the same schedule and nothing changes anymore (temps (differential as well as rate of change), watering, fertilizer ) and I use a mix that stays more consistent with time. My out of flask seedlings don't grow as fast at first but they look healthier, and I have a feeling they will catch up as they get older, and bloom on time.
Stone
Well-Known Member
A pH or 2 or 12 is mighty extreme, and may very well alter the structure of the dissolved minerals, if not be damaging to the roots themselves, but my point was that the pH doesn't have to be a close to neutral as you proposed.
Keeping in mind that plants can affect the pH of the rhizosphere, I have measured a pH of 4 in the reservoir of an S/H pot that had been watered with a fertilizer solution at 6.5 the day before.
There was no documented pH info in the "throughfall" data I have seen, but (and contrasting with Lance's comment), carbon dioxide from the air dissolves readily in water, and that equilibrium concentration gives a pH of roughly 5.4, so I think it's doubtful that it's too much different, with only about 15 ppm TDS.
I define "rainwater" as rain that has just hit a solid object and has not had time to absorb anything. Nor has it had time to sit at low altitude and exchange gas.
Rainwater measured pH7.0 and dripping "rainwater" during a period of falling rain from epiphytic moss around orchids measured also pH7.0
Moss samples collected from 50 different spots in the same forest during the same 30 minute period were placed in a bag and mixed together.
Half of the moss was removed and all water was squeezed out of the moss into a sample cup. This sample contained mostly rainwater but also any moisture or juice that could be squeezed from the moss itself.
The field result was:
pH5.9
ec 0.25
102ppm
The other half of the moss sample was allowed to rest in the plastic bag overnight and then the water was squeezed out and tested.
Results:
pH5.5
ec 0.3
119ppm
pH 4.0 is very close to being considered a food preservative acidic level and lethal to most microbes so I doubt most orchids would flourish at that level.
Ray I explained in the post above about my contrasting reading.
I don't see how we can consider water as rainwater once it has landed on the ground and starts reacting with solid compounds of even CO2 from the atmosphere. I collect rainwater in tanks and when it comes out of our tanks the pH has dropped because of the CO2 gas exchange but it has not picked up any nutrients. Throughfall water and rainwater are different in their pH. My observations while standing in the rain and looking at orchids indicate that most of the water volume that contacts the orchid roots have a near neutral pH in the free flow water.
I have some further observations to expand on this but unless someone asks I won't bother.
pH 4.0 is way to low and dangerous for most plants.
For the record, I'm well past a year and only have 3 issues: the backward spicerianum, the slow-growing resorbing nutrient roth (not unusual best I understand it), and the slightly better growing St Swithin which also resorbs new old leaves. Everything else seems happy and is putting out new growths without much issue. The K-light seems to work for me.
I will try a little hard tap with the roth and spicerianum and see what difference that makes....
As regards pH: germination medium is set at about 5.4-5.8. I don't think maintaining a near neutral pH is important.
This is a very interesting thread. Seems the major variables are:
micro supplementation
water quality
urea vs NH4 vs NO3 N
ppm N
watering frequency
lighting level
humidity
Perhaps some enterprising soul can try their luck tabulating as much data from this thread under the above headings and see if there is a trend... I'm too busy.
So 6.5 Ph works or not?
I've read posts about measuring the Ph of the water that comes out of the pot, but could never see any point in doing that. I can only control what goes in. What comes out seems to be irrelevant to me.
Also, the water comes out so fast, I wonder if the Ph could actually be affected that fast. Maybe, the exit water could be used to tell if the medium was going bad.
Have you ever watered mounted plants at Ph4? That would show if a Ph that low works of not.
No, but keeping the pH above 5.0 and below 7.5 is probably an important factor.
If not for the acidity factor then controlling the cause of of low or high pH.
Measuring the out flow and comparing the difference to the inflow will give you and idea of what was consumed between waterings.
pH6.5 is very good.
When measuring the pH or ec of the water coming out of the pot it needs to be done using a small controlled amount of water. Then it somewhat represents what the media moisture contains. The measurement of water that comes out fast is of not much use.
bullsie
Well-Known Member
My desert roses, Adenium obesum, loved the K-lite. I bought a handful of tiny seedlings. Watered them with the orchids with K-lite and growth was phenomenal. 4-6 inches of growth and nice big fat bases forming in five months. I've never had them grow so well. Am pleased!
The folks at Greencare add citric acid to their fertilizers to enhance solubility. Because of that, my applied solutions have been in the 5.0-5.5 range for years.
However, it is NOT the pH of the applied solutions that matter (unless they are too extreme, of course), it is the resulting pH of the rhizosphere (roots and medium) that's important. That can be more accurately assessed by measuring the pH of the pour-through.
With my applied fertilizer at pH=5.0-5.5, or at 6.5, the pour through I measured was consistently in the 5.5-5.8 range.
As to the pH in a S/H reservoir, this was an investigation that was done by several of us quite a few years ago. The pH varied drastically, based upon the time of day it was measured. If you measured a complete refresh with a pH=6.5 solution immediately, that's what you'll read. When we measured it after several hours of sunlight, and it had changed. Measuring it again after the plant was sitting in the dark overnight, when different biological processes had occurred, and the pH was different again, only to return to the prior level after more daylight.
I do recall seeing 4.0, but frankly don't recall if that was the day-, or night reading.
However, it is NOT the pH of the applied solutions that matter (unless they are too extreme, of course), it is the resulting pH of the rhizosphere (roots and medium) that's important. That can be more accurately assessed by measuring the pH of the pour-through.
With my applied fertilizer at pH=5.0-5.5, or at 6.5, the pour through I measured was consistently in the 5.5-5.8 range.
As to the pH in a S/H reservoir, this was an investigation that was done by several of us quite a few years ago. The pH varied drastically, based upon the time of day it was measured. If you measured a complete refresh with a pH=6.5 solution immediately, that's what you'll read. When we measured it after several hours of sunlight, and it had changed. Measuring it again after the plant was sitting in the dark overnight, when different biological processes had occurred, and the pH was different again, only to return to the prior level after more daylight.
I do recall seeing 4.0, but frankly don't recall if that was the day-, or night reading.
Ray,
I don't know how you can conclude this. How do you explain epiphytes in-situ as they relate to the relevance of water in a pot??? If the Ph of the applied water is not important how do in-situ orchids manage? Rainwater is about 7, I think.
I think that the roots absorb and hold water and maybe nutrients when they are watered. They do this in the velamen that surrounds the root. They then release the stored goodies as the plants need it. By the time everything is released from the velemen the orchid should need to be watered again i.e it's dried out. If it stays wet too long it needs to be repotted.
Maybe Ph5 works.
Lance,
I can understand that, but then why do I want to know that. Shouldn't the medium dry out within a couple days of watering?
The media never actually dries out completely. it might look dry but it's not.
However, The reason you want to know the difference is because it tells you what is going on in the pot. If you add fertilizer at 100ppm every week and a month later your pour through shows a reading of 200ppm... then you know your plants are not consuming the nutrients as fast as you add them....then you know you can and should reduce the dose of your fertilizer.
Even though the surface water has dried out between waterings you still get a reference reading using the pour through. That is because when the water evaporates from the pot it leaves the nutrients behind in the form of soluble salts. Immediately when the pour through water hits these salts they dissolve into the water and will register on the ec (ppm) meter.
You also get a glimpse of what the media pH is with the pour through. If you pour through water at pH7.0 and it comes out reading pH5.0 you know your media has a pH of less than 5.0.
Ray as orcoholic said this assumes that the orchid roots are ating like normal roots and extracting nutrients from the soil through CEC. But There is good argument to believe that orchid roots get their nutrients directly from the flowing water that contacts the roots. If that is true then the pH of the irrigation water may be more important than the pH of the media. And that may explain why you can have a pH4.0 in the media and the orchid plant is not suffering from it.
How much of a factor was the daylight? Did you try keeping the plant dark to see if the pH still dropped? The pH drop may also be from microbes and not the orchid roots. Possible or not?
Sounds sound. Thanks.
But how do I know which nutrients aren't being used? - or does that even matter? And, don't all salts register on a TDS meter the same?
I would assume that if your plants are growing well there's no reason to look at the pour through. If they're not, suppose it is because of a lack of a particular element. When you take a look and see that there is excess fert in the pour through and you reduce it, you'll be further starving the orchid for that particular element.
From the pour through test you don't know what nutrients are in the water you only know the total. The TDS meter measures all salts in the water combined.
It matters which nutrients are being used and you "assume" the fertilizer you are applying has the correct nutrients in the correct ratio so you can use the pour through to measure the use and strength of the complete nutrient supply. If you saw a huge difference in the pour through the only way to know which nutrients are being used more is to to a water test, and that is beyond the ability of most hobby growers. Experienced growers who monitor the ec and do a series of water tests learn that once they get the formula correct it remains the same for long term.
That's right. The only reason would be if you wanted to learn more about what's going on in the pot or if you want to grow the plants even better. OR if you want to get the same results by using less fertilizer you need to know if you are applying more than is needed already.
The lack of a particular element is diagnosed by the physical appearance of the plant or by chemical analysis. If you have a lack of an element you would not want to reduce the total fertilizer strength you would add in the missing element. But here it can get more complex (and simple at the same time). A problem caused by the lack of an element may not bebecause there is not enough of that element in the fertilizer. It might be caused by and excess of another element that caused an antagonistic reaction and the plant cant use the one element even though there is plenty available. So assume you have a fertilizer with plenty of every element in it and you are dosing heavily and you see a symptom of a nutrient shortage. If you did a pour through and the TDS was low you could simply increase the fertilizer dose and solve the problem (maybe). If the pour through showed high nutrient content then you might assume that there could be an antagonistic situation and reduce the fertilizer dose to see if that helped.
All the meter tests do is measure the total strength of all the salts and give you an idea of what to think and a clue in waht direction to move.
Paphman910
Well-Known Member
I never bothered with Klite! Cost of shipping is expensive and I don't want to be flagged because I am importing nitrate product into Canada!
In my case, I just use regular fertilizer and grow it warm year round. I use 25-10-10 and 20-20-20 and 15-30-15 alternating at times. I use about 1/4 teaspoon per gallon. I supplement with CalMag as well. No rocket science here!
Our water is so good that the pH is just about neutral and low in TDS for about 20ppm out of the tap!
I only grow multifloral paph species WELL because their requirements are met!
I am also interested in the geology of the habitat of the orchid species as it give you more insight into what type of soil they grow in.
In my case, I just use regular fertilizer and grow it warm year round. I use 25-10-10 and 20-20-20 and 15-30-15 alternating at times. I use about 1/4 teaspoon per gallon. I supplement with CalMag as well. No rocket science here!
Our water is so good that the pH is just about neutral and low in TDS for about 20ppm out of the tap!
I only grow multifloral paph species WELL because their requirements are met!
I am also interested in the geology of the habitat of the orchid species as it give you more insight into what type of soil they grow in.
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