Steve Johnson wrote: ↑Tue Jan 30, 2024 5:17 am
Chindit wrote: ↑Mon Jan 29, 2024 6:10 pmJust one other thing--and this may be a stupid question--but when you say "lean out" soil mix do you mean remove some old soil and mix in the new stuff, or re-pot the entire plant in a new mix?
Not a stupid question, the terminology needs to be more precise:
- Lean = mostly mineral gravel, some soil with minimal organic material. The mineral component promotes free drainage and good aeration of the roots. The soil component is for moisture retention.
- Rich = soil with a significant amount of organic material (usually tree bark). Fine for leafy plants, not fine for cacti because a soil-heavy mix suffocates their roots.
There's nothing wrong with organic material per se, but too much of it can be a pathogen "trap" over time. If you repot your cactus with a 60% mineral/40% soil mix, it'll be lean enough to do the job. With that said, ideally you should repot with fresh mix every 3-4 years. By the way,
never leave old soil in the pot, and clean it out of the roots as thoroughly as possible. You're contending with years of compacted soil, and water is the only way to loosen it. Swish the roots around in a container of water, then gently tease the soil out of the roots with a blunt instrument like a q-tip handle, knitting needle, etc. If roots come out in the process, chances are they're dead anyway. Don't worry about it -- your cactus will grow new roots in the lean mix.
Chindit wrote: ↑Mon Jan 29, 2024 6:10 pmThe fertilizer i have been using are drops by Schultz 2-7-7 Cactus plus. I was originally using it every couple of weeks in Spring, Summer and Fall, but had cut back to once in Spring, once in Summer and once in early Fall. (I was adding 7 drops per quart of distilled water).
A couple of problems there. First, the Schultz 2-7-7 is horrible stuff -- not nearly enough nitrogen, way too much phosphorus. The basic "rule of thumb" we follow is "P lower than N, K higher than both". Unfortunately there's not one fertilizer "specially formulated for cacti and succulents" that gets it right. Oddly enough, we do have an orchid fert with the NPK balance more suitable for your cactus:
https://www.amazon.com/Fertilizer-13-3- ... 725&sr=8-5
Water-soluble granules, dilution is 1/4 cup per gallon of water. I only use liquid concentrates, so I don't know how long it'll take for the granules to dissolve. Shouldn't take long, though. The other problem -- you have your cactus on a starvation diet. If you water every 2 weeks during spring and summer (my recommendation based on using a lean mix), fertilize with every other watering.
While we're on the subject of watering...
There's only one way to water in the growing season -- deeply, as in water coming out of the pot's drain hole. Of course that'll mess up your floor, so you can avoid it by doing this:
- Put a pan down on the floor.
In the fall and winter, you can give your cactus some occasional light watering (no fertilizer) -- just enough to moisten the mix without drenching it. By "occasional", I mean every 3-4 weeks.
Chindit wrote: ↑Mon Jan 29, 2024 6:10 pmAnd also in the second photo with the calluses you circled--should I perform "surgery" on that one also?
Not unless you see blackish areas on the callused rib. The biggest callus could be a trouble spot. I need to see the entire cactus, so please post a photo of it pot and all. A close-up of the potential trouble spot would also be helpful. From there we can determine the best course of action if you're dealing with a worst-case scenario. If it comes to pass, but the roots are healthy enough to grow under the better conditions I'm recommending, all is by no means lost.