CHC question

[larryt]

Hi All,

I need some advise on re-potting a couple of phals in CHC.

I bought a small compressed bale of CHC. When I pulled some off to rinse and soak I noticed that there is quite a lot of fiber as well as the chunks. Would it be wise to pick out the chunks and use them only or is it all right to include the fibers along with the chunks?

I have rinsed the CHC four times and they have been soaking for over 24 hours now, I tasted the water and there seems to be no salt taste and I plan to rinse them again before using.

Looking forward to your advise.

Cheers,
Larry

[BGGraham1]

Hi Larry. I'm no expert, but I did find a really great article on Ladyslipper.com about CHC. Sorry I didn't grab the link, bit they went into great detail about how they prepared it for repotting, including soaking it in water with calcium nitrate and Epsom salts. I just printed it out yesterday.

[JLu]

Larry, I have used a TDS meter to measure the rinse water from CHC. First, I clearly had considerable dissolved solids in the first soak. I assume that was sodium chloride. After 3 soaks the dissolved solids were very low and I never had any issues with using the CHC triple washed.

I think it best to use a soak for the first two or three rinses to give the salt time to migrate from the interior of the chips. It's quite likely that is a diffusion controlled rather than solubility controlled process. I would recommend the last rinse to be under running water or poured water. The chips can never have less salt than the level in the soak water..that's why a running water rinse seems like a good idea to me.

Good luck

PS..Brigitte was posting at the same time I was. I, too, have seen some suggestions about adding other salts to the rinse water. Chemically that makes no sense. Sodium chloride is very water soluble (as are all the salts she mentioned calcium nitrate and magnesium sulfate). There is no displacement type activity that occurs by adding other stuff and the solubility of sodium chloride is not improved. There is likely no reason to add other salts and actually they could be a negative (though it's unlikely). When you add to the salt content you must get that out also and the addition of other ions to the solution slightly reduces the solubility of all of them. As I say the effect is not really likely to be detectable because sodium chloride is so soluble in water, it seems silly to me to add things that you need to get out again and that don't perform a useful purpose by being there.

PS2..I think this idea came from someone who knows that some salts are only slightly soluble and the solubility can be improved by adding certain ions to a solution. For example calcium carbonate is nearly insoluble in water. Adding ions to produce soluble salts ( say sodium acetate) can cause calcium carbonate to be very soluble by producing sodium carbonate and calcium acetate both of which are very soluble. That's the whole theory behind the stuff that removes calcium carbonate from faucets,,whatever the heck that stuff is called.

In the case of the sodium chloride in CHC that's not an issue.

[Andrew]

JLu,
From my understanding it's not the solubility of the Na that's the problem; it's the high CEC combined with the high K content. The K is not easily released by soaking in water so adding salts of Mg, Ca, Fe, etc compensates for the high K load. K competes with the uptake of these other ions by the plant.

[BGGraham1]

Thanks for the explanation, JLu. I just read it over yesterday, and although I didn't mention it, they did do a soak with the calcium nitrate and Epsom salts, but then I think another soak and rinse or two with clean water.

I will never, ever claim to understand the science stuff. I just buy what I like and grow what I can. Its still a learning process.

Now, that being said, I also recall Ray using the same soak for the Prime Agra. Would you say that it make more sense for an inert media than CHC or bark?

[JLu]

Lost me Andrew. I don't know why the potassium content is high and if it is I don't see why it wouldn't be easily removed with the same rinses as used for the NaCl. Virtually all potassium salts are extremely water soluble.I also see no reason that the additional ions do anything. CEC should not be an issue at all in an orchid pot, just in soil that is expected to hold fertilizer for future use. In an orchid pot we are directly supplying the fert to the plant roots and essentially just washing the excess through. I can't see CEC being any issue at all.

Back to the beginning...I've used a lot of CHC successfully. It is no longer one of my favorites, but only because I've found other things I like better including LECA for plants that outgrow pots frequently like Catts. Getting all the CHC out is a nuisance. With LECA you put the whole mess in a bigger pot and fill in with more LECA. The rinses of CHC certainly show a quick reduction in dissolved solids content. If there is some problem with potassium that I don't understand, it never bothered me any. Maybe ignorance is bliss. But I certainly don't see any way that these other ions would improve any problem that does exist.

[Bolero]

I prefer to remove fines and any loose fibres from the CHC. I try and keep to the chunks and have a few Phals doing really well with it as a mix.

[larryt]

Thank you Bolero for answering my question

[pikkumyy]

thanks for asking the question larry, im going to be putting my phals in pure CHC when it gets a bit warmer, and im thinking of doing the same with my Onc's, but a smaller size

[larryt]

I did do one Onc. yesterday and hope it works out, time will tell

Cheers,
Larry