Candidate for rerooting?

[fanaticactus]

My E. rigidissimus v rubispinus bloomed once last summer and after that did nothing. I took it out of the pot and found most of the roots were gone, and there may have been a touch of mealybug. I've given it a long soap bath, gone over it lightly with an old toothbrush to clean the spines, sprayed it with alcohol and insecticidal soap. It seems OK now, except for no roots. I've rooted many cacti over the years but always wondered if I was doing it the best way. First of all, does this look like a viable candidate for growing new, healthy roots? It's fairly good sized: about 3.75" tall and averaging 2.5" wide. [By the way, the whitish areas on the base are a combination of old stuck-on rooting powder (does it stain spines?) and pulverized perlite. I don't why it all didn't wash off, but I'm not so concerned with that now. It's not mealies.] To root, should I use a standard gravelly mix or a bit finer sand or some potting mix? Should I moisten the base of it (light spray) to get some rooting compound to stick--or should I not use rooting compound at all? How deep should I put it in the gravel? Just enough to support it and cover the grayish old section? And, I should NOT water it at all, correct? Lastly, should it be placed in a warmer, shadier spot or in half or full sun?

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[DaveW]

Mine did the same thing about a year or so ago and took a season to get going again, but now seems to be OK. Cut or pull off the dead roots and tissue back to healthy tissue as new roots would have to force their way through all that hard dead stuff, allow it to callous over for a week or so and then re-plant. You can also dust the cut surface with flowers of sulphur or rooting powder to help it to callous if you like.

[fanaticactus]

Mine did the same thing about a year or so ago and took a season to get going again, but now seems to be OK. Cut or pull off the dead roots and tissue back to healthy tissue as new roots would have to force their way through all that hard dead stuff, allow it to callous over for a week or so and then re-plant. You can also dust the cut surface with flowers of sulphur or rooting powder to help it to callous if you like.

Thanks, Dave. And the rest of my procedure appears to be OK?

[greenknight]

My preference is to reroot in straight grit. I figure that since they can't take up water very fast at first, an extra free draining medium is safer; the soil won't go sour where the roots don't reach yet if there's no soil.

I set them back at the level they were growing, stabilize with little stakes if needed. Place in a bright. shaded location, increase the light gradually as you start to see growth. Check for root growth regularly, give a little water when roots appear. Once they have a fair-size root system, rinse roots clean and pot into your normal cactus mix, gradually start treating normally. Water very cautiously until the roots have reached the bottom of the pot.

This is what's worked for me, at least. I've only had to do this a couple times. My Echinopis ancistrophora lost its roots, a year later it was blooming again. A Parodia haselbergii was the first one, I rooted it in regular cactus mix and ended up having to do it over. That's when I switched to rooting in grit, and had better success.

[CactusFanDan]

These only seem to want to do anything when it's really hot here. Try to keep it as warm as possible when re-establishing it, preferably stick it on a heat mat if you can.

[Saxicola]

My preference is to reroot in straight grit. I figure that since they can't take up water very fast at first, an extra free draining medium is safer; the soil won't go sour where the roots don't reach yet if there's no soil.

I grow mine in pure pumice all the time, so you might not want to only root it in grit or pumice but keep it there. I get small ones in from a wholesaler that I then sell on Ebay. I find if I keep them for too long in the Coir based mix he uses (i.e. they don't sell fast enough or I get lazy and don't repot them) then I get some that rot or just don't want to make roots.