H
Hera
Guest
Quick question, does delenatii need calcium in the medium? I just read it grows on granite so perhaps not.
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Stone
Well-Known Member
All plants need Calcium but if these grow well in sphag and crypt-moss (both very acidic) it means calcium carbonate (limestone etc) will not be needed for pH control for at least 6 months. If you use calcium nitrate or have Ca in your water, (most municiple waters have lime added to slow/stop corrosion and leaching from copper pipes) then you can probably disregard Ca entirely. I've grown thousands of plants of all kinds (inculding limestone cacti, aloes, ferns, perrenials, trees, bromeliads and orchids) for many years without any Ca supplementation whatsoever (only what was in the mains water) for years without any problems at all.
The 2 most important things for delenatii from what I understand are no lower than 16C and never let them dry out.
The need for Ca is way overstated IMO. Just don't worry too much about it
My delis are outside in winter in Brisbane - down to 8C, occassional.
Oh, and I stopped adding calcium to the mix because you guys (on the forum) said not to....
H
Hera
Guest
I recently top dressed my paphs with crushed limestone then read about the delenatii growing on granite so that lead to me wondering if I should take the limestone off. Our water is full of minerals and is also very alkaline and I''ve been moderating that problem with vinegar. I shoot for a ph of around 7. They are growing in bark, charcol, and spongerock.
The Orchid Boy
Well-Known Member
I saw something very interesting at our show when we were setting up.... I was putting a delenatii in a display and noticed a very heavy pot. I looked and it was grown in limestone rock (like the driveway kind) and a little perlite and charcoal. I had never seen such a delenatii with such vibrantly variegated leaves. Forgot to ask about it and didn't get a picture of the leaves.
Stone
Well-Known Member
Hera, It seems like you are trying to acidify your hard water-which is ok-but then if you add crushed limestone you are back where you started. If you have highly mineralized water it could be counter productive to add lime to anything in your collection. I would remove all the limestone and see how the plants do without it. What is the pH of your water before you add the acid (but after it has been standing for 24 hours)?
H
Hera
Guest
Now I am glad I asked this question. My ph is around 10.5 uncorrected straight out of the tap. I haven't let it sit out overnight because it just doesn't fit in with my watering approach. When I have time to water it's a fit it into the schedule kind of thing. That's why I've used the vinegar to adjust. Its quick and I can add it to the water right at the sink. I fertilize very lightly and flush often.
So, you are saying that adding limestone reduces acidity which reverses the acidifying I've been doing with the vinegar. Wow, that makes sense in hindsight . I am repotting soon so all the limestone will be discarded. Thanks, I still feel like a noob sometimes.
So, you are saying that adding limestone reduces acidity which reverses the acidifying I've been doing with the vinegar. Wow, that makes sense in hindsight . I am repotting soon so all the limestone will be discarded. Thanks, I still feel like a noob sometimes.
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10,5 pH????IMPOSSIBLE!!!!!!!
H
Hera
Guest
No, not impossible I'm sad to say.
Ive been told that citric acid is a better way of correcting pH as its unlikely to precipitate other elements/nutrients.
Stone
Well-Known Member
Before I moved my pH was between 9 and 11
Did you live in a limestone cave, Mike?
Rick
Well-Known Member
The pH of Oklahoma City water comes off the tap in excess of 10 like that.
The hardness is not phenomenal and more due to alkali mangnesium and silicate with poor gas balance. Oklahoma is on sandstone with no limestone except in the Ozarkian Eastern edge of the state.
(Serpentine has very low Ca but exceptional high pH like this).
In Oklahoma I would aerate the water for 24 to 48 hours and the pH would drop down to 7.5.
You can make this go much faster (seconds) by bubbling a little CO2 through the water. Bottled CO2 gas is not hard to get.
I used to plow a bunch of lime into my pots to counteract pH drop and work on the incorrect notion that some plants had special calcium needs. (all plants need calcium). Generally this never made any plants better.
Most of the pH drop in your pots is due to excess nitrogen being applied. If you cut your feed rate way down then the pH will hold up fine without pot supplements.
The hardness is not phenomenal and more due to alkali mangnesium and silicate with poor gas balance. Oklahoma is on sandstone with no limestone except in the Ozarkian Eastern edge of the state.
(Serpentine has very low Ca but exceptional high pH like this).
In Oklahoma I would aerate the water for 24 to 48 hours and the pH would drop down to 7.5.
You can make this go much faster (seconds) by bubbling a little CO2 through the water. Bottled CO2 gas is not hard to get.
I used to plow a bunch of lime into my pots to counteract pH drop and work on the incorrect notion that some plants had special calcium needs. (all plants need calcium). Generally this never made any plants better.
Most of the pH drop in your pots is due to excess nitrogen being applied. If you cut your feed rate way down then the pH will hold up fine without pot supplements.
