Keep this coir or not?

[fanaticactus]

Two days ago I visited my local greenhouse/garden center to see what cacti I could pick to help replenish my collection. This is the same place that last year I complained to that in many of their cacti I found root mealies when it was time to repot. I suggested they should pass this on to their supplier and perhaps he would be more vigilant about this problem. I also said I would not be buying any more from them last season to either give the supplier time to clean up his act or even change supplier--but I stated it a bit less bluntly than that. This year their stock seemed much better but most of the soil mix stayed wet, dense and muddy. I always had to look for rot as well as insects. Two days ago their stock was almost entirely depleted but I was able to get a nice Parodia and Mammillaria. Today I unpotted them in preparation for repotting in my new pumice mix, and I discovered they were both potted in what looks like pure shredded, fibrous coir. This is the first time ever I've seen this at this garden center. The cacti look super healthy and have a very thick and extensive root system. I've pulled out a lot of the coir but am hesitating to pull out any more out of fear of tearing away the established root system. The coir is only slightly damp and, obviously very loose, allowing for a lot of air around the roots. Is it advisable to leave the remainder of the coir among the roots now that they are mostly "freed up" to spread and just put the whole thing into pumice? I'd like to know where coir shredded this fine can be bought; I looked online and everything I saw was in brick form. And, by the way, I've been horribly disappointed at both Home Depot and Lowe's this year and their supplies of cacti. I've been to those stores many times and all they have are those hideous glued strawflower monstrosities, which I will not buy. Their selection is extremely limited this year as well.

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[DaveW]

Looks almost as if they have been grown with hydroponics coir being the support medium, especially with such an extensive set of feeding roots you would not get in conventional potting soils? The Mamillaria camptotricha? or is it a Dolichothele? looks extremely bloated, however with less over feeding it will revert to normal again.

http://www.just4growers.com/stream/grow ... coir!.aspx" onclick="window.open(this.href);return false;

Coir comes in compressed brick form to save space when carting it half way around the world (at least to the UK) in atmospheric polluting shipping from coconut producing countries (how green is that as a local peat replacement?) You have to break up the bricks as in the link below:-

http://therealgarden.com/2011/02/coconut-coir-tutorial/" onclick="window.open(this.href);return false;

Why restrict yourself to buying from local stores with a limited selection when there are numerous specialist cactus nurseries in most countries who will ship by post or carrier? Try Cactus Mall to find them:-

http://www.cactus-mall.com/nurseryusa.html" onclick="window.open(this.href);return false;

[fanaticactus]

I wasn't sure exactly which species of Mamm it is; I was thinking maybe "longimamma", "magnimamma", "sphacelata" or "sphaerica". When you say "bloated", I guess you're referring to the light green areas where the tubercles are more widely separated than they should be. That area was flat up against the side of the pot and half immersed in the coir, if that partly explains it. Thanks for the tutorial on how to break up the bricks. That must be what I want anyway. Is it necessary, though, to test for salinity or add the gypsum, as he does in the photos? If I'm reading correctly between the lines, it seems as if you're indicating it would be OK to keep the coir around the roots when I replant into the pumice? Now that I've seen the great root structure that can be achieved with coir, is it advantageous to use a mix of pumice, diatomaceous earth/clay, gritty sand and coir as a usual mix?

[fanaticactus]

Oh, I forgot to mention that I do rely more and more on online sellers for my cacti. The one I am most comfortable with here in the States is Miles to Go. Very reasonably priced, low shipping rates, fast shipping and super quality--and Miles will promptly answer any questions by e-mail. I like Corona Cactus, too, but I'm not sure if he's still maintaining his regular online catalog and sales. Last time I checked, his site was more of a blog than sales. I also tried another with very good quality, but their postage was very high and for that reason I probably won't buy from them again.

[DaveW]

Sorry I have never used coir, but a few did in the UK some years ago. Anyway I found these for you:-

http://www.tucsoncactus.org/html/growin ... _2013.html" onclick="window.open(this.href);return false;

http://www.bcss.org.uk/foruma/viewtopic ... hilit=Coir" onclick="window.open(this.href);return false;

Don't know if you have to wash the salt out of today's coir I am afraid. Would not think you needed to add anything fertilizers with trace elements did not supply. I was simply saying with all that root it looked as if they had been grown in a water based hydroponics system rather than in conventional potting mixes which are watered occasionally.