Yet another example of "Less is More" with Feeding
- Thread starter Ray
- Start date
Help Support Slippertalk Orchid Forum:
I know- but I've read that if you're gonna make kelp-tea to use as extract it smells while "cooking" Never tried to make though- besides, I would probably mess up something. (The reason for reading about that was to see if I could make something that would give me some of the benefits of the kelp- it contains more than 60 different goodies) Kinda like diy kelp-tea.
Lol- welcome to the jungle- up in the cold north Thats kinda awesome though
Edit: I think I might sound a bit dumber when I write in another language than norwegian Harder to explain
Lol- welcome to the jungle- up in the cold north Thats kinda awesome though
Edit: I think I might sound a bit dumber when I write in another language than norwegian Harder to explain
I can tell you from first-hand experience that crippled flowers are, indeed, a result of overexposure to auxins.
Forgetting "less is more" for a moment, you should all know that my longtime philosophy is "nothing exceeds like excess", so several years ago I tried one tablespoon per gallon of K-L-N at every watering, and after a few months, deformities occurred in phalaenopsis. Granted that was a very large dose, in addition to frequency.
More recently, I tried the same thing with KelpMax, where one tablespoon per gallon is the preferred dose, but I applied it at every watering for a month, and I saw deformities in oncidiums and paphs.
Fortunately, it is quickly reversible, and in all cases, the plants bloomed normally the next time around, once the OD was stopped. It's apparently a "near term" affect, too, as in the KelpMax case, plants that were earlier in spike that fully bloomed a few weeks later, were unaffected.
There have been plenty of tests of hormone excess on plants and it does very often result is deformed flowers and growth irregularities.
Be careful though when you just say less, that can be taken literally and depending on a person's media, he /she might end up having micro nutrients deficiency, which is quite hard to fix after the fact. These guys are saying less to NPK but they also supplement for the other important stuff which is usually not mentioned in this kind of topic.
If one use very low ppm but apply it every watering that is just the same as applying the total of those fert at one time but less frequently. If one has the equipment to do this automatically then the low ppm every watering is a better practice. If one is a sprayer and do this mix every watering this might not be the way to go.
Now looking at Ray's application of 1TBSP/gal, now I can relate to his "less is more" approach.
Stone
Well-Known Member
Yes it is imprecise, and could probably have been expressed in a better way.
No not mycorrhizae as such (although it could be part of it) but any vigorous population of beneficial (or harmless) micro-organisms will suppress other microbes. If you have a vigorous population of beneficial microbes, then the harmful will have a tougher time in multiplying and cause problems to you. That is the priciple behind stuf like inocucor. Of course if you spray physan, you kill off the harmless population and leaves the door open for pathogens.
It is probably not so much the type, but that there is enough beneficial organisms present that will suppress pathogens.
No not mycorrhizae as such (although it could be part of it) but any vigorous population of beneficial (or harmless) micro-organisms will suppress other microbes. If you have a vigorous population of beneficial microbes, then the harmful will have a tougher time in multiplying and cause problems to you. That is the priciple behind stuf like inocucor. Of course if you spray physan, you kill off the harmless population and leaves the door open for pathogens.
It is probably not so much the type, but that there is enough beneficial organisms present that will suppress pathogens.
myxodex
Well-Known Member
Maybe it would be interesting to collect some figures for N feeding rates here.
I do get the less is more idea, and if approx 20 ppm N with every watering is low then I'm in the low camp, but surely we cannot expect to carry on diluting our feeding rates and expect to see a continous improvement. There must be a range that finds a compromise between the safety of less and the dangers of too much. There is a theoretical argument for a lower end to this range at about 30 ppm N as NO3. I'd thought about posting this in a previous thread but to be honest it is rather technical and I'm not sure how much I believe in it either, ... but it does offer a different way of thinking about plant nutrition that might just about be worth bearing in mind, anyway here goes, ...
It is all to do with the cost of nutrient acquisition. We could think of this in units of glucose produced by photosynthesis, how many units go to respiration to cover the energy costs of the plant and how many to supply the carbon backbones of the organic building blocks of new plant biomass. I was surprised to learn that the estimates of the cost of nutrient uptake to the plant range from 20 - 50 % of it's total energy budget, ... thats a lot !
Before I give the rational for 30 ppm NO3 as a lower limit, a little digression into the extremes of too much, just to lay out a broader perspective. Plants under significant stress don't grow well. It is well known that stressed plants exhibit crazy high respiration rates, and indeed, abnormal respiration rates have been used as a measure of stress (along with ethylene emission). Very high nutrient levels can cause stress, but we're talking way above that which anyone here is likely to use. Let me give an example, the plant tissue culture medium Murashige and Skoog at half strength, as used for orchid propagation, has a total N over 400 ppm (140 as NH4 and 275 as NO3), the K comes in at 470 ppm (as K2O). Not all orchid seedlings will grow on this medium, but many will and it is widely used. This medium also has a high sucrose concentration without which the plants would not survive, irrespective of their photosynthetic capacity. It has been said by one worker in plant tissue culture that ..." they grow under sugar mitigated stress ". When plants are exposed to high nutrient levels they are being force fed, i.e. they cannot stop the influx of ions and they use a lot of ATP pumping K+, NH4+ and H+ out of the cells to restore normal physiological concentrations and to reset the membrane potential, and this is the cause of most of this stress related respiration. If they don't have a lot of surplus glucose to burn up they are in trouble.
The concentration of nutrient ions in the root zone has an impact on the cost of their uptake, there is a thermodynamic limit that evolution has had to work around. The result is that for each of the macronutrient mineral ions there are at least two, if not three or more genes for transporter proteins. The high affinity transporters (HATS - active uptake) are used when nutrient levels are low, and low affinity ion channels (LATS - passive uptake) when nutrients are abundant. HATS uptake at low concentration is more expensive than LATS, ... but, ... it is not that clear cut because LATS isn't cost free either (dont be misled by the "passive uptake" label) . The plants under high feeding regime are doing LATS uptake, the influx of cations, K+, NH4+ causes membrane depolarisation and the root cells are wired up to correct this by pumping out H+ to compensate the charge balance and so restore the membrane potential. This uses ATP, and hence glucose. If they are also taking up NO3 at the same time the depolarisation is less and so this cost is partly offset. On the other hand at low concentrations, i.e. HATS uptake, there is a fixed cost that can't be offset, one molecule of ATP for each nutrient ion taken up. The thing about HATS transporters is that plants regulate how many of these they make. If for example the K is very low, they make lot more K-HATS transporters in an attempt to meet the K demand. So there is a significant extra synthetic cost here on top of the 1 ATP per K+. If you increase the K they make less and so on. This is why our plants are so adaptable, they adjust to our feeding regime as best they can, but this adaptability has an extra cost at very low and very high feeding rates, so less glucose goes into building new plant and more into respiration.
So is there a sweet spot, or an optimal range at which we can minimise the number of units of glucose used to take up our feed ? I suggest at the lower end of the LATS range, at least for NO3. So at what concentration does HATS transport give way to LATS transport ... it's between 1 and 2 mM for most ions; for the cations NH4+ and K+ it's just over 1 mM and for the anions NO3- and PO4-- it's nearer 2 mM. Translated to ppm of N as NO3 this comes to 28 ppm, for N as NH4 it's bit over 14 ppm. For K (as K2O) it's 47 ppm and for P (as P2O5) it's about 71 ppm. Possibly with K, but more especially with P, these high levels would be inviting other problems, but given that N is the nutrient with the highest demand, feeding at 30 ppm N as NO3 puts NO3 into the lower end of the passive uptake range. In a previous thread Brabantia reported a big improvement in growth with a change from 20 ppm N to 40 ppm N, I assume the fert was mainly N as NO3, then this increase neatly crosses the threshold for passive uptake of NO3 with a bit to spare.
The curious thing with this result is that I seem to remember quite a few folk here are feeding in the 30 - 50 ppm N range.
I do get the less is more idea, and if approx 20 ppm N with every watering is low then I'm in the low camp, but surely we cannot expect to carry on diluting our feeding rates and expect to see a continous improvement. There must be a range that finds a compromise between the safety of less and the dangers of too much. There is a theoretical argument for a lower end to this range at about 30 ppm N as NO3. I'd thought about posting this in a previous thread but to be honest it is rather technical and I'm not sure how much I believe in it either, ... but it does offer a different way of thinking about plant nutrition that might just about be worth bearing in mind, anyway here goes, ...
It is all to do with the cost of nutrient acquisition. We could think of this in units of glucose produced by photosynthesis, how many units go to respiration to cover the energy costs of the plant and how many to supply the carbon backbones of the organic building blocks of new plant biomass. I was surprised to learn that the estimates of the cost of nutrient uptake to the plant range from 20 - 50 % of it's total energy budget, ... thats a lot !
Before I give the rational for 30 ppm NO3 as a lower limit, a little digression into the extremes of too much, just to lay out a broader perspective. Plants under significant stress don't grow well. It is well known that stressed plants exhibit crazy high respiration rates, and indeed, abnormal respiration rates have been used as a measure of stress (along with ethylene emission). Very high nutrient levels can cause stress, but we're talking way above that which anyone here is likely to use. Let me give an example, the plant tissue culture medium Murashige and Skoog at half strength, as used for orchid propagation, has a total N over 400 ppm (140 as NH4 and 275 as NO3), the K comes in at 470 ppm (as K2O). Not all orchid seedlings will grow on this medium, but many will and it is widely used. This medium also has a high sucrose concentration without which the plants would not survive, irrespective of their photosynthetic capacity. It has been said by one worker in plant tissue culture that ..." they grow under sugar mitigated stress ". When plants are exposed to high nutrient levels they are being force fed, i.e. they cannot stop the influx of ions and they use a lot of ATP pumping K+, NH4+ and H+ out of the cells to restore normal physiological concentrations and to reset the membrane potential, and this is the cause of most of this stress related respiration. If they don't have a lot of surplus glucose to burn up they are in trouble.
The concentration of nutrient ions in the root zone has an impact on the cost of their uptake, there is a thermodynamic limit that evolution has had to work around. The result is that for each of the macronutrient mineral ions there are at least two, if not three or more genes for transporter proteins. The high affinity transporters (HATS - active uptake) are used when nutrient levels are low, and low affinity ion channels (LATS - passive uptake) when nutrients are abundant. HATS uptake at low concentration is more expensive than LATS, ... but, ... it is not that clear cut because LATS isn't cost free either (dont be misled by the "passive uptake" label) . The plants under high feeding regime are doing LATS uptake, the influx of cations, K+, NH4+ causes membrane depolarisation and the root cells are wired up to correct this by pumping out H+ to compensate the charge balance and so restore the membrane potential. This uses ATP, and hence glucose. If they are also taking up NO3 at the same time the depolarisation is less and so this cost is partly offset. On the other hand at low concentrations, i.e. HATS uptake, there is a fixed cost that can't be offset, one molecule of ATP for each nutrient ion taken up. The thing about HATS transporters is that plants regulate how many of these they make. If for example the K is very low, they make lot more K-HATS transporters in an attempt to meet the K demand. So there is a significant extra synthetic cost here on top of the 1 ATP per K+. If you increase the K they make less and so on. This is why our plants are so adaptable, they adjust to our feeding regime as best they can, but this adaptability has an extra cost at very low and very high feeding rates, so less glucose goes into building new plant and more into respiration.
So is there a sweet spot, or an optimal range at which we can minimise the number of units of glucose used to take up our feed ? I suggest at the lower end of the LATS range, at least for NO3. So at what concentration does HATS transport give way to LATS transport ... it's between 1 and 2 mM for most ions; for the cations NH4+ and K+ it's just over 1 mM and for the anions NO3- and PO4-- it's nearer 2 mM. Translated to ppm of N as NO3 this comes to 28 ppm, for N as NH4 it's bit over 14 ppm. For K (as K2O) it's 47 ppm and for P (as P2O5) it's about 71 ppm. Possibly with K, but more especially with P, these high levels would be inviting other problems, but given that N is the nutrient with the highest demand, feeding at 30 ppm N as NO3 puts NO3 into the lower end of the passive uptake range. In a previous thread Brabantia reported a big improvement in growth with a change from 20 ppm N to 40 ppm N, I assume the fert was mainly N as NO3, then this increase neatly crosses the threshold for passive uptake of NO3 with a bit to spare.
The curious thing with this result is that I seem to remember quite a few folk here are feeding in the 30 - 50 ppm N range.
Very interesting. I like stuff like this.
Questions:
For 30-50 N, what percent is NH4?
Should this concentration be available to the plant, (roots and leaves) everyday during the growing period?
Is this an average daily intake?
I can see non-polarization is important here, the suggested supply of P could be for that reason, could we sub some of the P with something else?
This is good stuff.
Questions:
For 30-50 N, what percent is NH4?
Should this concentration be available to the plant, (roots and leaves) everyday during the growing period?
Is this an average daily intake?
I can see non-polarization is important here, the suggested supply of P could be for that reason, could we sub some of the P with something else?
This is good stuff.
No takers here Myxodex. I think you scared them with those amount of K and P you mentioned. LOL. It just a discussion.
But I like your approach in using efficiency and balancing charges. It's the kind of stuff engineers can relate better. I was actually intrigued about these two topics and researched about them. There's this paper/study I found about balancing charges on the roots/plant. Basically saying cations and anions have to be balanced in the plant or the plant will take up these ions available to it with some preference to balance the charges. I have seen this topic here but they only touched the N uptake, maybe I haven't seen them yet, but I asked myself, what's in exchange to K uptake or NH4 or Ca or Mg to balance the charges? It can't be NO3 all the time or the plant will accumulate so much NO3. There's got to be a different anion source/s other than P, NO3 and S to balance the cations.
This questions I have led me to organic fert.
Ok, I think I'm done. Sorry for hijacking your topic Ray.
But I like your approach in using efficiency and balancing charges. It's the kind of stuff engineers can relate better. I was actually intrigued about these two topics and researched about them. There's this paper/study I found about balancing charges on the roots/plant. Basically saying cations and anions have to be balanced in the plant or the plant will take up these ions available to it with some preference to balance the charges. I have seen this topic here but they only touched the N uptake, maybe I haven't seen them yet, but I asked myself, what's in exchange to K uptake or NH4 or Ca or Mg to balance the charges? It can't be NO3 all the time or the plant will accumulate so much NO3. There's got to be a different anion source/s other than P, NO3 and S to balance the cations.
This questions I have led me to organic fert.
Ok, I think I'm done. Sorry for hijacking your topic Ray.
Not scared. It's a lot of info that needs thought before comment.
But my first thought is you cant really come up with a valid set of numbers because of all the variables possible in the growing environment. And you cant use data from soil growing plants on epiphytic orchids... At least I dont think so.
The information sounds very logical, and I really like that. Whether they are factual, I don't know, but as it was stated as being so, and I have no knowledge or information that may contradict that, I'm OK to accept it at face value, until we learn something better.
Lance is right that the adaptability of the plants and the variables of cultural parameters make it a pretty tough thing to nail anything down, but it's great for discussion.
Here, where folks are all too quick to criticize, I will simply say "Thanks, Myx!"
Lance is right that the adaptability of the plants and the variables of cultural parameters make it a pretty tough thing to nail anything down, but it's great for discussion.
Here, where folks are all too quick to criticize, I will simply say "Thanks, Myx!"
I usually assume other factors to be ideal so I can concentrate understanding how the numbers were obtained. For me, the principle behind it is more important than the numbers. One can get his/her numbers by factoring in his/her unique conditions after obtaining the ideal number.
If this is assumed to be optimal, then this range has to be available to the plants 24/7. This means every watering and to be consistent, leaching is done first to avoid build up.
Now let's factor in reality, one is media, if one is using bark then one needs to budget extra N and the N-grabbing critters. The efficiency and preference of the roots to take up the kind of N must also be factored in. The latter I think is still not well undestood. He laid it out but did not exactly elaborate why P and NO3 were selected to balance the cations and K as the preferred cation. This is what got my attention.
You can factor in the environmental conditions and you get your number.
Very interesting Myxo,
I do also like your approach, but think that it is too easy to focus on one thing and forget the others. Translated, that means if we focus on growth, we may lose on health. Just as an example: fat people may utilise food better than slim people but are not necessarily healthier (although they can be)
The same applies to plants, a maximum nutrient uptake may give the biggest plants, but they may suffer healthwise. The rate of growth is the easiest to measure though, so most people go for that.
Plant health and immune system is a topic that is only partly understood, but it depends on a range of factors. One of them is the condition of the epidermis, how easy is it for a pathogen to enter and establish? Secondly if it enters, how well is the immune system prepared to be able to counter-strike the attack?
Here the nutrient uptake plays a role. First of all, if the growth is too fast, the epidermis normally lags behind in the hardening or toughening. The same happens if there is a lack of some more uncommon nutrients, Silicon is the most important here. to my knowledge almost no fertilisers contain silicon. In nature, some Silicon is normally available as dissolved monosilicic acid (comes from decaying plants matter, not sand etc.)
This is normally not so in orchid growing. Here we repot as soon as there is a chance of liberating (decaying compost) some dissolved silica
The Silicon strengthens the epidermis and participate in the internal production of chemicals that is supposed to defeat the invading pathogen. Not always sucessful, but less sucessful if the conditions are sub-optimal.
Back to nutrition and N level. I am convinced that the healthiest plants are obtained if their conditions resemble what they have been adapted to in nature. Or as close as possible to that.
Looking at pictures of paphiopedilums in nature, particularly their habitat and other plants, there is one thing that strikes one. Namely that many Paphs grow in an environment poor in nutrients. Typical place is with moss and sedges in a water seepage, and if the water is analysed, it may contain a lot of different things - but is more often than not very poor in essential nutrients like N.
In pot culture, with restricted roots etc. I would assume that the plants need more nutrients than in nature, but perhaps less than we think?
I do also like your approach, but think that it is too easy to focus on one thing and forget the others. Translated, that means if we focus on growth, we may lose on health. Just as an example: fat people may utilise food better than slim people but are not necessarily healthier (although they can be
) The same applies to plants, a maximum nutrient uptake may give the biggest plants, but they may suffer healthwise. The rate of growth is the easiest to measure though, so most people go for that.
Plant health and immune system is a topic that is only partly understood, but it depends on a range of factors. One of them is the condition of the epidermis, how easy is it for a pathogen to enter and establish? Secondly if it enters, how well is the immune system prepared to be able to counter-strike the attack?
Here the nutrient uptake plays a role. First of all, if the growth is too fast, the epidermis normally lags behind in the hardening or toughening. The same happens if there is a lack of some more uncommon nutrients, Silicon is the most important here. to my knowledge almost no fertilisers contain silicon. In nature, some Silicon is normally available as dissolved monosilicic acid (comes from decaying plants matter, not sand etc.)
This is normally not so in orchid growing. Here we repot as soon as there is a chance of liberating (decaying compost) some dissolved silica
The Silicon strengthens the epidermis and participate in the internal production of chemicals that is supposed to defeat the invading pathogen. Not always sucessful, but less sucessful if the conditions are sub-optimal.
Back to nutrition and N level. I am convinced that the healthiest plants are obtained if their conditions resemble what they have been adapted to in nature. Or as close as possible to that.
Looking at pictures of paphiopedilums in nature, particularly their habitat and other plants, there is one thing that strikes one. Namely that many Paphs grow in an environment poor in nutrients. Typical place is with moss and sedges in a water seepage, and if the water is analysed, it may contain a lot of different things - but is more often than not very poor in essential nutrients like N.
In pot culture, with restricted roots etc. I would assume that the plants need more nutrients than in nature, but perhaps less than we think?
Thats the reason why I bought ProTekt Aint getting it from decayed media in my house
It helps with the uptake of some micronutritions I believe. (Lol, gotta do some more reading before I comment any further on these things.)
I like this thread, so many things to go do a search and read more about.
Thanks
It helps with the uptake of some micronutritions I believe. (Lol, gotta do some more reading before I comment any further on these things.)
I like this thread, so many things to go do a search and read more about.
Thanks
Hahaha I'm worst. I have lots of questions from reading. Some I say them here to spark conversation. Pick some brains. Just be vigilant with this plants because they will show signs when they 're not happy
Sent from my HTC One using Tapatalk
Sent from my HTC One using Tapatalk
naoki
Well-Known Member
Thank you, Tim, for interesting way to look at this. I'll need to learn more about the actual mechanisms of uptake (Marschner's book seems to have good review about this topic).
Bjorn, obesity in plants could be interesting. It does an appeal from animal centric view, but I wonder if the animal logic applies to plants. Most of the time, people talk about nutrient deficiency and susceptibility to disease. I haven't seen many info about this topic. Toxicity is studied, but without going to extreme, are plants growing slower really healthy? In nature with lots of unpredictability and seasonal change, growing as fast as possible is not a good idea. They can't support themselves to go over the tough time (dry spell, cold temp etc). So it is a part of the reasons why epiphytes or succulent grow slow.
I'm not sure if epidermis is influenced by the growth rate, though. But there is no doubt that root:shoot ratio is influenced by the level of fertilization (and watering).
Also, with regard to the mineral nutrition, the last factor you mentioned (limited space in pot) seems to be a big deal to me. In most of the paphs studied in the nature has extensive association with mycorrhizal fungi. In the pots, they have much less association (you can still isolate mycorrhizal fungi from greenhouse cultivated plants). In some plants, the fungi can dramatically increase the soil contact area. In 1 cubic cm of soil, there may be only a couple cm of roots (and root hairs), but there could be 50m of hyphae! So they may be growing in nutrient poor environment, but overall uptake may not be as low as you think from looking at the soil analysis or stem-flow data. In other words, natural condition may be a good starting point, but it may not be the best as Mike has been saying.
I do get impressed by Ray's plant, so thank you for posting this, Ray. Almost no mineral nutrients provided, and it's in inorganic media. Then it flowered in 18 months from the flask. It seems to be almost impossible! But this tells us that orchids are probably well buffered in terms of mineral nutrients, much more than temperature tolerance (of some orchids). I don't see lots of difference by changing fertilization scheme, but I see drastic effects in temperature change at the time scale of 1-2 months. Well, this is probably obvious to many, but it is related to Mike and Bjorn's comments that the plants are not in the optimum condition: a deviation in a couple degrees of temperature makes the growth slower and mineral nutrients aren't the limiting factors in many cases.
Bjorn, obesity in plants could be interesting. It does an appeal from animal centric view, but I wonder if the animal logic applies to plants. Most of the time, people talk about nutrient deficiency and susceptibility to disease. I haven't seen many info about this topic. Toxicity is studied, but without going to extreme, are plants growing slower really healthy? In nature with lots of unpredictability and seasonal change, growing as fast as possible is not a good idea. They can't support themselves to go over the tough time (dry spell, cold temp etc). So it is a part of the reasons why epiphytes or succulent grow slow.
I'm not sure if epidermis is influenced by the growth rate, though. But there is no doubt that root:shoot ratio is influenced by the level of fertilization (and watering).
Also, with regard to the mineral nutrition, the last factor you mentioned (limited space in pot) seems to be a big deal to me. In most of the paphs studied in the nature has extensive association with mycorrhizal fungi. In the pots, they have much less association (you can still isolate mycorrhizal fungi from greenhouse cultivated plants). In some plants, the fungi can dramatically increase the soil contact area. In 1 cubic cm of soil, there may be only a couple cm of roots (and root hairs), but there could be 50m of hyphae! So they may be growing in nutrient poor environment, but overall uptake may not be as low as you think from looking at the soil analysis or stem-flow data. In other words, natural condition may be a good starting point, but it may not be the best as Mike has been saying.
I do get impressed by Ray's plant, so thank you for posting this, Ray. Almost no mineral nutrients provided, and it's in inorganic media. Then it flowered in 18 months from the flask. It seems to be almost impossible! But this tells us that orchids are probably well buffered in terms of mineral nutrients, much more than temperature tolerance (of some orchids). I don't see lots of difference by changing fertilization scheme, but I see drastic effects in temperature change at the time scale of 1-2 months. Well, this is probably obvious to many, but it is related to Mike and Bjorn's comments that the plants are not in the optimum condition: a deviation in a couple degrees of temperature makes the growth slower and mineral nutrients aren't the limiting factors in many cases.
You may be right naoki, obesity in plants does sound strange, and looking at it from that perspective....? Nevertheless my observations can be condensed into:
1) they grow just as fast (or faster?) with low fertiliser levels(e.g. 20ppm N) than with higher nutrient levels (e.g. 100ppm N) and producing just as much - or more biomass
2) seemingly the rate of decease incidents has been reduced.
Of course this does not necessarily have to do with the fertiliser level, since so many other things have changed in parallell - it could be due to other factors like availability/non-availability of some micro-nutrients.
The latter is examplified by the fact that leaf-analyses mostly show rather high sodium levels, sometimes similar to P2O5, but nobody fertilises with it. Probably since its always there? But what if it is not?
just a thought:evil:
1) they grow just as fast (or faster?) with low fertiliser levels(e.g. 20ppm N) than with higher nutrient levels (e.g. 100ppm N) and producing just as much - or more biomass
2) seemingly the rate of decease incidents has been reduced.
Of course this does not necessarily have to do with the fertiliser level, since so many other things have changed in parallell - it could be due to other factors like availability/non-availability of some micro-nutrients.
The latter is examplified by the fact that leaf-analyses mostly show rather high sodium levels, sometimes similar to P2O5, but nobody fertilises with it. Probably since its always there? But what if it is not?
just a thought:evil:
sodium - a good indication...
30 years ago I visited the natural location of Paph. niveum on the Langkawii Islands.
Some niveums grew only 1 to 2 meters above the water surface directly on the rocks and have been regularly humidified by seawater (the same as godefroyae): 10710 ppm Na, 1290 ppm Mg, 415 ppm ca, 385 ppm K (analyzes from the internet).
But most of the Paphs. are growing at the crest of the island in a yellowish friable loam.
I took a soil sample with to allow them to analyze:
162 ppm N, 28 ppm P, 101 ppm K, 3255 ppm Ca, 301 ppm Mg and 42 ppm Na.
A chemically preloaded orchids friend gave his 4 niveum additional sodium - unfortunately I never asked him in what concentration.
His niveums had a leafspan about 40 cm and the inflorescence was 40 cm long - the flower had normal size...
30 years ago I visited the natural location of Paph. niveum on the Langkawii Islands.
Some niveums grew only 1 to 2 meters above the water surface directly on the rocks and have been regularly humidified by seawater (the same as godefroyae): 10710 ppm Na, 1290 ppm Mg, 415 ppm ca, 385 ppm K (analyzes from the internet).
But most of the Paphs. are growing at the crest of the island in a yellowish friable loam.
I took a soil sample with to allow them to analyze:
162 ppm N, 28 ppm P, 101 ppm K, 3255 ppm Ca, 301 ppm Mg and 42 ppm Na.
A chemically preloaded orchids friend gave his 4 niveum additional sodium - unfortunately I never asked him in what concentration.
His niveums had a leafspan about 40 cm and the inflorescence was 40 cm long - the flower had normal size...
