Ca and Mg again

[DavidCampen]

I do not believe it is the added citric acid which makes that the pH of the solution is acid. Since a few years I make all my fertilizers myself (yes I like experimenting). I was never able to conceive(design) a fertilizer which did not give a slightly acid reaction in deionized water. Citric acid is probably used as a chelator.

Yes, in my formulations, I use diammonium citrate to bring the pH up to 5.7-6.3, otherwise it would be at 5.0 or below in RO water, especially when using any ammonium nitrate in the formulation (I also add borate as boric acid).

 

[ALToronto]

Ray, I use a 4000 ppm N concentrate (33 g powder in 1L water) to mix up my fert solution. I don't think I could hit 10 ppm N with a single crystal of the powder - it would be in excess.

Without fert, my RO water is 7-10 ppm tds, and a pH of 7.5-7.8. I don't know why it went up with K-lite. Certainly if I spill some concentrate on the (traditional) concrete countertops in my kitchen, I get an acid-etched spot.

Probably time to recalibrate my pH meter and go through this exercise again.

Tom, you're right that this is active growth season. But the rate of growth of the catts on the wall, compared to the ones still in pots, is significantly higher.

 

[Ray]

I agree on the calibration check - both pH & TDS.

Pure water, when exposed to the CO2 in the air, should give you an equilibrium pH of about 5.4 (maybe lower now that the global average has gone from 300- to 400 ppm). I cannot imagine what would increase it so much at that low TDS

 

[Brabantia]

I agree on the calibration check - both pH & TDS.

Pure water, when exposed to the CO2 in the air, should give you an equilibrium pH of about 5.4 (maybe lower now that the global average has gone from 300- to 400 ppm). I cannot imagine what would increase it so much at that low TDS

Just as remark: It is very difficult to measure the pH of a solution presenting a very low conductivity such as RO water. This is only possible by using very special electrodes and adapted electronics ... it costs a lot of money!

 

[Stone]

Here's a sobering observation!
Last night one of our members (who grows just about every paph and phrag as well as many other things) brought in a couple of things and I asked him what he feeds.

Answer: He uses a ''professionally made'' stuff at 3 times recommended concentration on everything every week and waters like hell. He was not sure of the NPK but you can bet it wasn't low in K! He said he would not recommend it (and niether would I) but that's what he does. (Forces the crap out of everything and nothing going backwards yet) He grows everything in plain fine bark and that's it.
He benched 2 Paphs. 1 multi growth delenatii bursting out of its pot and one nice multi growth concolor with 7 inch leaves.
We still have much to learn!

I must say this notion of long term health problems really does not make sense. If you grow a plant to its optimum potential, (not so much forcing as above) and keep it coming, there is no rational reason why it should suddenly - or slowly- start a decline after a period of time. The problems come about when you start to neglect it through boredom or laziness or whatever.

Remebering that ''optimum'' is different for every plant and discovering what is optimum for each species can be difficult to impossible, It cannot be justified that a plant with nice big green leaves AND a healthy vigorous root system AND which holds on to its old leaves, is lacking Calcium, Magnesium or is intoxicated with Potassium. Its just not possible.

One of the first signs of Ca deficiency is dead or dying roots. And without them nothing else works. If it was low in Mg it cannot have dark green leaves. You can't have plenty of Mg in the chlorophyll and have K blocking it at the same time!

Fear of potassium still looking a bit misguided to me. Just don't use too much and there will be no problem.

 

[Brabantia]

But the rate of growth of the catts on the wall, compared to the ones still in pots, is significantly higher.

I agree, Catts are growing faster than Paphs. Unless using as some producers higher doses of fertilyser (600 - 800 µS) and in an optimal environment. At present here Catts in pots are growing crazy at 400 µS (3/1/2 fertilyser) one time per week. I am always surprised noticing that Catts are able of growing so fast with so few fertilizers while with slightly less Paphios limp along.
I believe that it is in connection with the quantity of roots or a slower metabolism ?

 

[Stone]

Catts are able of growing so fast with so few fertilizers while with slightly less Paphios limp along.
I believe that it is in connection with the quantity of roots or a slower metabolism ?

Paphs can grow fast. Many are flowered in 18 months from flask. That is much faster than a Catt. The secret is uniterupeted growth from as soon as you pot them untill they are mature. Not always easy for me at least!

If you make a mistake with a paph, it is very difficult and slow to get it back to fast growth again. Sometimes 1 year, sometimes never! You have to find a way to keep the roots happy in your conditions. Every one is different but to me it seems that a good clean mix, lots of water, and high humidity is a good start. When it is growing well you can feed a lot. When it isn't, it's hard to know what to do.

 

[ALToronto]

I agree, Catts are growing faster than Paphs. Unless using as some producers higher doses of fertilyser (600 - 800 µS) and in an optimal environment. At present here Catts in pots are growing crazy at 400 µS (3/1/2 fertilyser) one time per week. I am always surprised noticing that Catts are able of growing so fast with so few fertilizers while with slightly less Paphios limp along.
I believe that it is in connection with the quantity of roots or a slower metabolism ?

I'm comparing growth rates of only catts. Most of mine are mounted, but I have a few that are potted as well - three in semi-hydro, four in bark/coconut, and two in lava rock. Of the potted ones, the semi-hydro group is doing best - but then again, I used to have a lot more in semi-hydro, and I had to pull most of them out before they died. Now the semi-hydro refugees are mounted and are doing much better.

 

[ALToronto]

Mike, that's interesting about overdosing the fertilizer. I suspect that 'watering the hell out of them' means flushing with plain water, so overall, the fertilizer concentration is much more dilute. I'm sure the guy didn't tell you everything.

If I showed my concrete recipe to someone who is familiar only with traditional concrete, they would insist that my product wouldn't hold together. And yet it's far stronger than anything that comes out of a mixer truck. There are ways to push the envelope, but you really need to know what you're doing.

 

[Stone]

There are ways to push the envelope, but you really need to know what you're doing

.

Very true!