Culture document

[Rick]

Ultimately I think the base understanding is how much nutrients actually flux through the environment that orchids grow in, and then understand the science that produced the fertilizer regimes that we ultimately were taught to use.

Bottom line is that the amount of nutrients that jungle orchids see in the wild is a fraction of the amount we use in culture (regardless of individual constituent level).

Present fertilization regimes were developed for corn (and wheat, rice, potatoes). Food crops that we want to grow VERY quickly and produce large amounts of sugary starchy fruit to eat, and then discard. All growth and maximum edible production in 9 months.

The primary use of K in plants is for sugar production.

Orchids have evolved to need VERY little carbohydrates and live virtually forever with very little energy output. The seed of orchids have no carbohydrate/starch stores to feed the embryonic orchid (they use mycorhrizae to feed the embryonic orchids until they gain their own photosynthesis). This is because K is actually very rare in the environment. Most K in plants is recycled from earlier growth and the fallen leaves of trees they grow near. Over hundreds of years the trees (with roots in the actual mineral layer and in contact with ground and interstitial water) dredge and concentrate minute quantities of K and get it up to the surface where terrestrial and epiphytic plants can access a very small supplement to the recycle rate.

Corn, potatoes, tomatoes, and other plants are now fully domesticated. Because their life cycle is less than a year, humans have genetically selected for fast growth and high sugar production (which requires lots of K). Actually there is no such thing as wild corn. It is a mutant of only suspect ancestry that appeared coincidentally with the advent of humanity in the New World. It is completely dependent on the connection with humans to supply nutrients at a rate far in excess of what is available in the jungle.

This is where all the research dollars and science into plant nutrition has gone into, and us orchid hobbyist have just been piggy-backing on that research for the most part.

Low K was really the first step to see how much of the corn science was actually applicable to orchids. Realizing that, yes, many people have figured out how to make corn fertilizing work for some orchid species and hybrids under certain conditions can be done, but how can we apply what we know about orchids in the wild to improve on what we are doing for the species, and conditions that always seem to elude us.

 

[Rick]

If he was here in front of me, I would kiss him.

I always wondered about you Aussies

I can't wait to get back down for a visit:wink:

 

[keithrs]

I always wondered about you Aussies

I can't wait to get back down for a visit:wink:

To talk about orchid culture or for the kiss?oke:

 

[Rick]

To talk about orchid culture or for the kiss?oke:

Well actually I'll take a beer

 

[keithrs]

Well actually I'll take a beer

Sounds good to me!

Fosters... Australian for beer!:drool:

 

[Bjorn]

Sorry for interrupting, but has anyone investigated the pH of their irrigation water? If you read Xaviers manuscripts it seems clear that he thinks that optimum pH should be some 5.7 to 6. now, my experience is that the fertilizer has a significant impact on water pH, the k-lite giving a rater acid reaction. Under my conditions, that is fine, the water ends up at around pH 5, and since my substrate has loads of carbonate rock, that may explain the excellent results with k-lite that I am experiencing. Ok, would it not be possible that with other fertilizers, irrrespetive of their K content, could give other(higher) pH values and thereby block uptake of (mico)nutrients?
I will not touch the nitrate/urea problems here, but I have started some interesting testing.oke:
Very interesting thread btw.:clap:
Bjorn

 

[Stone]

I haven't changed anything else in the last few years. Just the fertiliser. At the end of the day, it is all about increasing the levels of Mg and Ca. I have done that as well as greatly reduce the K at the same time. I have also changed to using a foliar fertiliser a lot and also used the Magamp hose attachment so that I fertilise and water at the same time. So I have changed a few things at once so it is difficult to exactly pinpoint the cause. In the end I think it is the plants greater ability to access Ca and Mg that has seen an improvement in my Paphs. So I disagree strongly with your repeated statement that fertiliser is unimportant. Irrespective of whether you think it is low K or not, it is fertiliser that has turned my plants around.

I don't think I said fert was unimportant did I? Maybe I did? If so I should have put it better. I do think its important otherwize I wouldn't bother feeding all my orchids and I would not have about 10 different kinds lying around. In fact I have recently increased aplication with some in inert media to every watering! So yes Very important. But the subject at hand is the fact that you could not put down the plant improvement to a reduction in K. Why were the original growers achieving such large growths?
What I do believe is that feeding is most important when the plant is most reseptive, That is when the growths are 3/4 grown (in bulbous spp). With paphs...not so sure but probably a continuous gentle trickle of nutrients during the growing season and none during dormancy. Also important is the balance which we're all discussing here. It seems the plants can survive and even thrive on very variable amounts from almost nothing to almost lethal as long as the balance of elements is correct. And thats where opinions differ.
I will continue to look at the results of the low K diet with interest but without knowing all the variables (light, heat, solution strength, potting media type, media pH water quality, Calcium and Magnesium supplementation and what kind? bicarbonate or not..) its hard to make a concrete judgement.
I'm certainly not trying to win some crazy argument. If the low K theory was proved tommorow, I would get some or have it made in a flash! But for the time being I look at a result and ask myself questions like "what else has been changed that I don't know about?..Are you (whomever) seeing something thats not there? and can the supposed improvement be attributed to anything else at all? In your particular case it must be something else or at least partly something else. Ageed?

 

[Stone]

I always wondered about you Aussies

Don't lump me in here

 

[Stone]

How could a single controlled trial possibly give results that would be applicable to "growing plants in a huge range of ways and a vast variety of substrates".

If I had the money and resources, I could easily set up a trial with say 500 plants of say 25 species over a year (maybe 2) that would prove one way or the other no problem. We are just looking for the facts. Of course I don't have either money OR resourses:rollhappy:

 

[emydura]

I always wondered about you Aussies

I can't wait to get back down for a visit:wink:

We are a sensitive new age lot here now. But I'm willing to compromise and offer a beer instead.

David, what water do you use? Do you flush a lot?

I just use tap water. We have pretty low TDS here in Canberra. In the peak growing season I don't tend to flush a lot. Every fourth watering I don't use the MAGAMP hose attached fertiliser. So just use normal tap water. But then I follow up with the CMB fertliser to the potting mix. Not sure if you would call that flushing. In the cooler season I only fertilise every 2nd watering and at half the rate.

I don't think I said fert was unimportant did I? Maybe I did? If so I should have put it better. I do think its important otherwize I wouldn't bother feeding all my orchids and I would not have about 10 different kinds lying around. In fact I have recently increased aplication with some in inert media to every watering! So yes Very important. But the subject at hand is the fact that you could not put down the plant improvement to a reduction in K. Why were the original growers achieving such large growths?
What I do believe is that feeding is most important when the plant is most reseptive, That is when the growths are 3/4 grown (in bulbous spp). With paphs...not so sure but probably a continuous gentle trickle of nutrients during the growing season and none during dormancy. Also important is the balance which we're all discussing here. It seems the plants can survive and even thrive on very variable amounts from almost nothing to almost lethal as long as the balance of elements is correct. And thats where opinions differ.
I will continue to look at the results of the low K diet with interest but without knowing all the variables (light, heat, solution strength, potting media type, media pH water quality, Calcium and Magnesium supplementation and what kind? bicarbonate or not..) its hard to make a concrete judgement.
I'm certainly not trying to win some crazy argument. If the low K theory was proved tommorow, I would get some or have it made in a flash! But for the time being I look at a result and ask myself questions like "what else has been changed that I don't know about?..Are you (whomever) seeing something thats not there? and can the supposed improvement be attributed to anything else at all? In your particular case it must be something else or at least partly something else. Ageed?

Maybe it was the numerous references to people who never use fertilisers and still have great success that confused me. oke:

It is hard to be definitive about exact causes but I'm convinced it is mostly related to the fertiliser regime I now employ. I think that the fertiliser techniques I now use are more efficient in my plants accessing Ca and Mg. Previously I watered first and added fertiliser through a watering can afterwoods. As the potting mix is already saturated I don't think this is an efficient way of adding fertiliser as most would just flow straight out of the pot. Now I water and fertilise at the same time. I also now use a foliar fertilser a lot. I know many people on this forum are not convinced about the merits of foliar fertilisers. I checked with the company that produces CMB and they told me I could apply it as foliar or to the potting mix. But they said the foliar would be far more efficient and far more immediate. They are a pretty big company whose focus is mainly on commercial farmers so I accepted they knew what they were talking about. Previously the fertilisers I used had little or no Ca or Mg. I had to apply this separately through epsolm salts and a Calcium Nitrate fertiliser. While I tried to apply these on a regular basis I don't think I applied them enough. Now my orchids get Ca and Mg every time I water. The K I apply now is much lower than previous.

So there are a lot of factors here relating to fertiliser that could be the cause of the improvement. In the end I think my plants are getting a lot more Ca and Mg through a combination of the above changes.

 

[Rick]

Sorry for interrupting, but has anyone investigated the pH of their irrigation water?
Very interesting thread btw.:clap:
Bjorn

Maybe rather than pH I would like folks to know the alkalinity of their irrigation water and pass/pour through water.

pH is a rough surrogate for alkalinity measurements. Generally (but not always)
low pH is representative of a low alkalinity water.

But alkalinity is a measure of buffering capacity (via bicarbonate ion) which is quite different than the huge black box of pH measurement.

Alkalinity is measured by titrating a measured amount of sample against an acid of known concentration. When you add enough acid to hit a pH of 4.0 (~~) you can calculate the alkalinity (as CaCO3, or more importantly as HCO3)

Bill Argo (the creator of MSU) demonstrated a very good relationship between the form of nitrogen primarily utilized by the plants (ammonia vs nitrate) and the amount of bicarbonate ion in the system. Low alkalinity systems preferentially use nitrate while higher alkalinity systems use more ammonia. It's gradual (not redline) with systems in the 60-80 (ppm as CaCO3) and up range needing a higher percentage of ammonia.

This was used as the primary difference between the "pure water" or "rain water" versions of MSU versus the "well water" version.

pH also will modify the uptake availability of various nutrients (major and micro), but the sweet spot is actually fairly broad with overlap for the different nutrients. There is a table of optimal pH ranges for nutrient uptake on the Antec reading room site (I've linked to this site multiple times over the years, so you guys can find it yourselves this time).

But the pH nutrient regimes can be over-ridden by aberrant alkalinity concentrations in pot conditions (especially if you load up the potting mix with carbonate bearing materials) so measuring pH alone is inadequate.

 

[keithrs]

Sorry for interrupting, but has anyone investigated the pH of their irrigation water? If you read Xaviers manuscripts it seems clear that he thinks that optimum pH should be some 5.7 to 6. now, my experience is that the fertilizer has a significant impact on water pH, the k-lite giving a rater acid reaction. Under my conditions, that is fine, the water ends up at around pH 5, and since my substrate has loads of carbonate rock, that may explain the excellent results with k-lite that I am experiencing. Ok, would it not be possible that with other fertilizers, irrrespetive of their K content, could give other(higher) pH values and thereby block uptake of (mico)nutrients?
I will not touch the nitrate/urea problems here, but I have started some interesting testing.oke:
Very interesting thread btw.:clap:
Bjorn

I do check my pH fairly often. I use straight RO @ a pH of about 6.8-9 . After I add K-lite my pH gos down to 5.9. If I had kelp my pH will go down to 4.8-9, So I add "tap" water to buffer my RO when I use kelp to keep it around 5.5-6.

K-Lite drops my pH about as much as MSU... It been awhile since I used it but if memory serves me MSU(RO) pH was around 6-6.2.

 

[keithrs]

Why dont we stop b!tch'n like a bunch of broads and do some tests.....oke:

I'll pitch in a flask!!!

Then when the testing is done, we can sell or auction off the seedlings and profits can go to ST.

 

[Rick]

Why dont we stop b!tch'n like a bunch of broads and do some tests.....oke:

I'll pitch in a flask!!!

Then when the testing is done, we can sell or auction off the seedlings and profits can go to ST.

Pitch in a flask of emersonii or hangianum. Make it a real test.


I have a micro trial going on a dozen lowii seedlings (out of flask and in CHC).

Unfortunately for the space issue in my GH it's been hard to keep them from getting "contaminated" by everything else getting low K.

I can report that after a year none have died (6 of each fert). Given the variance in size at the start, I actually started with some of the bigger ones exposed to MSU (to avoid criticism that I biased the start for K lite plants).

They are all growing. A couple of the MSU plants are bigger than than any of the K lite plants, but they are very "floppy" in the pots, while the klite plants are definitely more securely rooted. Coming out of winter we'll see if the Klite plants pass the MSU, or if the MSU plants loose their roots and crash.

This is still not much of a test. And its surprisingly hard to control in a packed hobby GH all shifted to other feeding methods.

 

[gonewild]

If I had the money and resources, I could easily set up a trial with say 500 plants of say 25 species over a year (maybe 2) that would prove one way or the other no problem. We are just looking for the facts. Of course I don't have either money OR resourses:rollhappy:

That is my point....:wink:... No one person or even facility has the money to do such a trial.
To give the accurate dependable results you expect, 500 plants of 25 different species would be needed to test EACH variable.
How many different variables are there in orchid collections that would need to be addressed?
Assume only 10 variables and then you need 5000 plants.
But also some of the variables are environmental and that means different greenhouses for different environments. (adding variables within the trial)
But then how to trial windowsill growers or artificial light growers?
Too many variables so such a trial will never be done accurately or dependably.

A time span of one or two years as you mention won't prove anything. In two years almost all commercial fertilizers will give good growing results from the start of a trial. It is after the two years time that the long term toxicity problems begin to show up. So a complete trial would need to run many more years.

In the case we have here on ST with the K-lite use we are seeing how the low K ratios are effecting established collections and have the benefit of growers who know what to expect from their plants. When a grower notices that suddenly there are less problems with disease, sees more growths and overall better looking plants than they had before we have valid trial results where it relates to "orchid collections".

The argument that the improvements might be from other variables like Seaweed extract or micro nutrients or increased Calcium or Magnesium does not have merit because all of these variables have been tested before without seeing such dramatic results. The only variable that has not been tested before is the low K. So in the short time of K-lite trials it is fair to say that low K nutrient fertilizer is a benefit to growing an orchid collection.

We still don't know what long term use problems may arise with a low K diet but based on the decreased disease problem and increased growth we can assume the future would be good.

A grower has to learn how to grow plants long term, you can't read it in a book and just follow a recipe, because of all the variables.

Collectively the ST community has more orchid growing expertise than any single company or university. Members may not be horticulturists, botanists or trained scientists but they have a keen interest in their plants or they would not be here and for this reason the ST K-lite trial will yield valid results.

 

[keithrs]

That is my point.... No one person or even facility has the money to do such a trial.
To give the accurate dependable results you expect, 500 plants of 25 different species would be needed to test EACH variable.
How many different variables are there in orchid collections that would need to be addressed?
Assume only 10 variables and then you need 5000 plants.
But also some of the variables are environmental and that means different greenhouses for different environments. (adding variables within the trial)
But then how to trial windowsill growers or artificial light growers?
Too many variables so such a trial will never be done accurately or dependably.

I do think that there are enough species that grow in conditions that would be controllable in the average greenhouse to get a proven trial that can be done accurately.

A time span of one or two years as you mention won't prove anything. In two years almost all commercial fertilizers will give good growing results from the start of a trial. It is after the two years time that the long term toxicity problems begin to show up. So a complete trial would need to run many more years.

So your saying that the 1-2 years that K-Lite has been "tested" is not enough to prove that it is a 'better' fertilizer choice than others?

In the case we have here on ST with the K-lite use we are seeing how the low K ratios are effecting established collections and have the benefit of growers who know what to expect from their plants. When a grower notices that suddenly there are less problems with disease, sees more growths and overall better looking plants than they had before we have valid trial results where it relates to "orchid collections".

I can't say that I have not seen less diseased plant BECAUSE of K-Lite. I can say that I do have less disease, but I contribute that to other products.

The argument that the improvements might be from other variables like Seaweed extract or micro nutrients or increased Calcium or Magnesium does not have merit because all of these variables have been tested before without seeing such dramatic results. The only variable that has not been tested before is the low K.

Thats funny.... Ray(as well as others) have documented that kelp extract does have an effect on the plants.

So in the short time of K-lite trials it is fair to say that low K nutrient fertilizer is a benefit to growing an orchid collection.

Just like MSU showed us....

We still don't know what long term use problems may arise with a low K diet but based on the decreased disease problem and increased growth we can assume the future would be good.

Lets cross are fingers like we did with MSU

A grower has to learn how to grow plants long term, you can't read it in a book and just follow a recipe, because of all the variables.

I agree... which is why I think some of the results from K-Lite are from all the talk on there about pH, hardness, alkalinity, Ca:N ratio, TDS, PPM N, ect. has given others a better understanding of culture needed for these plants. Granted, K-Lite may be all its shaken up to be... but there may be a chance that it has even more side effects the MSU. Remember that almost of us have reduced the amount of N applied. I have cut mine by more then 4x. There may be a something to say for that?!? I would be interested in knowing what would happen if we reduced MSU down from 125ppm N to 30ppm N?

Collectively the ST community has more orchid growing expertise than any single company or university. Members may not be horticulturists, botanists or trained scientists but they have a keen interest in their plants or they would not be here and for this reason the ST K-lite trial will yield valid results.

Keen interest in there plants may be why after reading everything on here, they changed there culture resulting in better plants.

 

[Bjorn]

Maybe rather than pH I would like folks to know the alkalinity of their irrigation water and pass/pour through water.

pH is a rough surrogate for alkalinity measurements. Generally (but not always)
low pH is representative of a low alkalinity water.

But alkalinity is a measure of buffering capacity (via bicarbonate ion) which is quite different than the huge black box of pH measurement.

Alkalinity is measured by titrating a measured amount of sample against an acid of known concentration. When you add enough acid to hit a pH of 4.0 (~~) you can calculate the alkalinity (as CaCO3, or more importantly as HCO3)

Bill Argo (the creator of MSU) demonstrated a very good relationship between the form of nitrogen primarily utilized by the plants (ammonia vs nitrate) and the amount of bicarbonate ion in the system. Low alkalinity systems preferentially use nitrate while higher alkalinity systems use more ammonia. It's gradual (not redline) with systems in the 60-80 (ppm as CaCO3) and up range needing a higher percentage of ammonia.

This was used as the primary difference between the "pure water" or "rain water" versions of MSU versus the "well water" version.

pH also will modify the uptake availability of various nutrients (major and micro), but the sweet spot is actually fairly broad with overlap for the different nutrients. There is a table of optimal pH ranges for nutrient uptake on the Antec reading room site (I've linked to this site multiple times over the years, so you guys can find it yourselves this time).

But the pH nutrient regimes can be over-ridden by aberrant alkalinity concentrations in pot conditions (especially if you load up the potting mix with carbonate bearing materials) so measuring pH alone is inadequate.

Ok, I follow you fairly well, but there is one thing that puzzles me: If the pH is right (or for that sake wrong) and you disregard any reactions between the compost and the fertiliser mix, when the water hits the plants, how do the carbonate equillibria influence the pH afterwards? I mean when it hits the pot and wets the roots? Any adjustment of the pH has of course alteady been done before the irrigation.oke:
What I try to say (foreign languages make things difficult) is that perhaps some people have water or fertilizers or combinations thereof that result in water with a pH that is outside the optimum range of 5.7-6. After the addition of the nutrient of course. This would prevent at least some of the trace minerals to be available.
I have had good results using the k-lite. As a matter of fact exceedngly good. So per se, I am a follower. I have however fairly light colored leaves that I would like to make a bit greener. For this my previous experience told me that urea was the key. I have a test going that includes the addition of an urea based fertiliser that was incompatible to the k-lite. I do mix them though. This caused problems due to precipitation unless pH was brought down. I use citric acid as this also provides for an improved buffering action. As you know Rick, pH is defined as pH = - log(H+concentration) so a dilution from a stock solution at 10% diluted to 100ppm should give a pH increase of some 3 units-if it was not for the buffering effect of the mix. In my case the buffered mix at approximately pH 4.5 becomes an fertilizer mix at approximately 200ppm with a pH of around 5.8.
Calculating these things are almost impossible,testing is the easiest way.
The urea experimens (actually an improved micronutrient mix as well) is monitored, I started yesterday, and today as I made some photgraphs the leaves were already greener. Lets hope that trend continues if not, I have no proof for my allegations.

 

[katzenhai2]

But then how to trial windowsill growers or artificial light growers?
Too many variables so such a trial will never be done accurately or dependably.

Test one condition which can be established by most people and is in favor of the plants. Why fit the plants to our condition and not us to the plants condition? If it doesn't work for windowsill users they are not flexible enough to change conditions.

A time span of one or two years as you mention won't prove anything. In two years almost all commercial fertilizers will give good growing results from the start of a trial. It is after the two years time that the long term toxicity problems begin to show up. So a complete trial would need to run many more years.

I repot every plant almost every year in new substrate. So you are saying that there will accumulate a toxic level in the plants with too much K? Or do you assume plants get stressed and some time their metabolism says byebye because of the year-round stress of too much present K in the substrate?

 

[gonewild]

I do think that there are enough species that grow in conditions that would be controllable in the average greenhouse to get a proven trial that can be done accurately.

Yes there are. But the controlled trial is going to relate to that group of selected species. The results from the ST trials will give an overall result that represents the value when applied to a mixed collection under many different variables. We are not looking for the nutrition best for a mass commercial crop but rather what is best for a mixed collection with varying environmental conditions.

So your saying that the 1-2 years that K-Lite has been "tested" is not enough to prove that it is a 'better' fertilizer choice than others?

No. I'm saying the exact opposite. The fact that the plants are growing better (or as well) as with other fertilizer and the fact that there seems to be less disease points to the fact it is a better choice now.

I can't say that I have not seen less diseased plant BECAUSE of K-Lite. I can say that I do have less disease, but I contribute that to other products.

Why do the other products get the credit? Do you have some new products that other people have not tried before?

Thats funny.... Ray(as well as others) have documented that kelp extract does have an effect on the plants.

Sure it has effect on plants, never said it did not. But it does not have the same pronounced effect as the K-lite. Seaweed has been in use for a long time and personally I could only see minor possible positive results and it has not shown to prevent the disease problems that are now becoming less with the use of K-lite.

So in the short time of K-lite trials it is fair to say that low K nutrient fertilizer is a benefit to growing an orchid collection.

Just like MSU showed us....

NO. MSU never showed the positive result of reducing the disease outbreaks. Adding this positive benefit to K-lite puts it a step ahead.

Lets cross are fingers like we did with MSU

Time tells all. (controlled trials do not! )

I agree... which is why I think some of the results from K-Lite are from all the talk on there about pH, hardness, alkalinity, Ca:N ratio, TDS, PPM N, ect. has given others a better understanding of culture needed for these plants.

That may be the case for beginning growers but a lot of the good reports are coming from experienced folks that already have dealt with these things.

Granted, K-Lite may be all its shaken up to be... but there may be a chance that it has even more side effects the MSU

.

Possible. But long term deficiencies of nutrients in plants are easier to correct than excesses. Deficiencies tend to slow organisms down while excess tends to kill them.

Remember that almost of us have reduced the amount of N applied. I have cut mine by more then 4x. There may be a something to say for that?!? I would be interested in knowing what would happen if we reduced MSU down from 125ppm N to 30ppm N?

That one is easy. Plants grow slow and don't give the pleasing result as with a higher N rate. It is not the strength of the fertilizer it is the the balance of nutrients.

Keen interest in there plants may be why after reading everything on here, they changed there culture resulting in better plants.

Perhaps for many growers but as I said before a lot of the reports are from experienced growers that already had a handle on the other factors.

 

[gonewild]

Test one condition which can be established by most people and is in favor of the plants. Why fit the plants to our condition and not us to the plants condition? If it doesn't work for windowsill users they are not flexible enough to change conditions.

Yes doing a trial for a few conditions is easy but the comment I was addressing was regarding a complete trial that covers everything.

I repot every plant almost every year in new substrate. So you are saying that there will accumulate a toxic level in the plants with too much K? Or do you assume plants get stressed and some time their metabolism says byebye because of the year-round stress of too much present K in the substrate?

I'm not saying that, but I think Rick has said that he believes this may be the case. But I will say that it makes perfect sense and I tend to think it may be true.

I don't think it is too much K present in the substrate but rather too much K consumed and stored in the plant tissue. With the correct application of the correct balance of nutrients there should be no reason to repot every year.