Hello there my friends, I've been absorbing a lot of information from this forum posts but didn't quite found the answer to my problem. So I have come across some annoyances on my T. Pachanoi. I've bought it on-line from a reliable source (don't know if I can share the site for further elucidation). The cacti is a cutting and, as it arrived, I've checked if it was already callused on the bottom which it was. I let it rest for a week laying down and after that time I've put it in a mix of gravel and Soil. Around 65% gravel 35% soil. It was inside the house (attic) on a window that catches direct sun (with a little screen to avoid insects) from dusk till 2PM and indirect light till 9:30PM. After 3 weeks I've noticed that the top was greener and I thought i'ld check for root formation and I did, there were a big root coming out of the cacti which I thought was good enough to start watering. I repotted the cacti on the same soil (but put it a little deeper) and gave it 300ml of distiller water. Since then the cacti grew sick. One black spot on the next day, 2 black spots the day after and 3 black spots at the 3rd day. The spots increased in size for two more days and then halted. The growing of the black spots seems to have stopped but i don't know what to do to heal the cacti. 2 spots are a little soft and the other is hard. I also don't know why this happened, was it to soon to water? Was it a big of a shock? I don't know the PH of the soil as I deeply believe my pH meter is broken because of inconsistent results but will try to buy a new one today. I've also a T. peruvianus and some L. williamsi in other pot bought from the same house in the exact same soil water with the exact same distilled water which seem to be faring quite well.

I've also notified that the top half areoles are yellowed and the half bottom are white.

I've halted the watering since the cacti grew sick (this was 2 weeks ago). Should I return to water it or leave it till it heals?

I would attach a phot but don't know how. If any of you guys could help I'll be appreciated.

Pics would help a lot.

Without photos it is hard to say, but it is probably fine. Cacti do occassionally get blemishes for various reasons but that will usually heal to a callus. IME cacti really like the outdoors and natural rain/sun. If it is warm in your region I would recommend it. Attics also get quite hot during summer, and with stagnant air that might possibly be a problem.

I was able to attach a picture of the cacti in the first post. What do you think?

wow.. that looks bad.. worse than I was thinking.

did it possibly get frosted or something.

is it spreading?
if it spreads I would chop off 1/2" below the lowest dark spot, bring it in and let it heal, if its not spreading it may correct itself.

It was spreading until a couple of days ago. Now it seemed to have stopped. I've checked the pH and its 6 which is bad. I'm trying to correct it but don't have nothing but egg shells with me to correct it.

I've water it today so lets see how it reacts tomorrow.

I don't think it could be freeze as the min temperature over hear are 20°C

OUCHIES!
Poor baby, I have a happy 1 ft Peruvian, and when i saw this post i thought we had a similar problem but seeing that pic i noticed mine was much different.

My ruru has little black spots that kind our hollowed out and callused. I was thinking it was from insects, because i see a tiny spider web hanging from the spines every time i go check on her.

I Hope you figured out your problem, I would like to know how to avoid such mistake.

GL n Thnx for the post.

If min temp is 20C try putting it outside in a area with good sunlight. My pachanoi get natural rain 1-3 days a week and are very happy. Temp is usually 16-35C depending on how the weather is.

Those black spots will probably heal to a tan callus if the cacti is in a good environment, but they could be cut out if desired.