It is indeed important when you make a cut to remove rot, you cut back to entirely healthy tissue. Disinfect your cutting tool after each cut. If I were you I would take my time and poke with a pencil or small stick each part of the cactus which you suspect is infected. If it's mushy, it's rotten. Y...

I've been following the topics on fertilization and substrates on the forum for a while now. I started using a soilless mixture since last year and with that also came the issue on how to fertilize plants. Since my knowledge on the topic is very limited I followed a lot of the advice given on the fo...

Nice arrangement of globular and columnar cacti! How deep is that plantbed?

I use the metric system, so I measure in liters. It's easy to convert though using a program. To acidify I use a product called JBL pH-Minus ( https://www.jbl.de/?mod=products&func=detail&country=gb&lang=en&id=2325 ). I reported on my findings with it here: https://cactiguide.com/for...

That Fero looks in survival mode. I hope it plumps up soon. You kept it on moist substrate for 3 weeks? How bold.

So it's basically: 1 gallon of water + 3,5 ml Flora Micro + 3,5 ml Flora Bloom + 7 grams 0-0-52 potassium sulfate. When not storing a stock of diluted potassium sulfate, but rather adding it on the go, is distilled water, R/O water or rain water of importance? I acidify my tap water to 5,5 with oak ...

Fantastic! It's also widely available in Europe, thus ending my quest for Dyna-Gro. Thanks! Regarding the potassium sulfate, would the following product work: https://bionovanutrients.com/Bionova-K-20/10062Z ? Or perhaps this: https://www.aquascaper.be/en/potassium-sulfate-500-gr-k2so4.html ? What's...

Thanks keith for your reply. Flupiradifurone is a relatively new product on the market here. I've researched it and the compound was patented in 2015. According to the producer is it not a neonicotonoid, but some scientific articles do say it has a lot of similarities. It should be safer for bees th...

I have access to a few systemic insectides where I am at (Belgium, Europe) such as: Sanium concentrate (Protect Garden) - 25 g/l flupiradifurone - up to 8 weeks of protection Multisect (KB) - 5g/l acetamiprid - up to 3/4 weeks of protection Perfekthion (BASF) - 400 g/l Dimethoat All of these insecti...

I do love the look of those dark spines. It just started growing all of a sudden or did you recently repot?

Usually moisture meters don't work properly in porous substrates. I also see you have gravel as a top dressing and a plastic pot. Those two combined with non-porous soil could explain your situation. But again, don't entirely rely on moisture meters.

I’ve read 70% IPA takes longer to evaporate due to the lower alcochol content, which makes it more effective for disinfectant purposes. I don’t know how this translates to bug control though.

I think greenknight gave a good answer. I concur with anttisepp, it needs more light. Are you able to put it outside? I don’t have any experience with growing lights, but make sure it gets enough of it. Length as well as intensity. There are applications for smartphones with which you can measure li...

I don't know if Neem Oil helps against spider mites. I used it in the past for scale, but it can have adverse effects on the wax layer on some succulents.

Depends on what you got access to...
A quick way to temporarily knock them off would be isopropyl alcochol (2-propanol). A 70% concentration is often recommended, but I've used a 100% IPA on adult plants with no side effects. You have to move quickly though.