The Cal-Mag of my dreams?

[ohugal]

Hi Steve,

Making a sticky is a good idea. Some members of the cactus club i’m in also grow in a pure mineral substrate. It would be interesting to publish some guidelines for fertilizing in the form of an article (as long as it doesn’t revolve around the Dyna-Gro products).

[jerrytheplater]

However, "Derived from" doesn't matter for our purposes in determining NPK ratios -- all we need is the guaranteed analysis of P2O5 and K2O being reported on the fert's label. To repeat what Mike said in 2020 (using Dyna-Gro 7-7-7 as an example):

Steve, I was responding to your post in reply to mine. I said that no fertilizer contains P2O5 or K2O. You disagreed and posted labels with the K2O and P2O5 circled. I took that to mean that you were saying these fertilizers contained P2O5 and K2O in contradiction to me. I explained the "Derived from" section to show you what those fertilizers contain, and that none of it is P2O5 or K2O.

That is all I meant by what I posted.

[Steve Johnson]

Steve, I was responding to your post in reply to mine. I said that no fertilizer contains P2O5 or K2O. You disagreed and posted labels with the K2O and P2O5 circled. I took that to mean that you were saying these fertilizers contained P2O5 and K2O in contradiction to me. I explained the "Derived from" section to show you what those fertilizers contain, and that none of it is P2O5 or K2O.

That is all I meant by what I posted.

Fair enough.

Making a sticky is a good idea. Some members of the cactus club i’m in also grow in a pure mineral substrate. It would be interesting to publish some guidelines for fertilizing in the form of an article (as long as it doesn’t revolve around the Dyna-Gro products).

Hi ohugal,

Because my experience is confined to the Dyna-Gro 7-7-7, I'll be using it as a point of reference on what growers should look for when they're considering various ferts. If my teaching skills are any good at all, they'll be able to understand the basic principles that apply to the ferts they can find regardless of whether it's Dyna-Gro or other manufacturers. Still have some work I need to do before I post the sticky.

[ohugal]

Yeah, sure, no rush.
I think I'm not allowed to promote specific products in articles. Regardless of Dyna-Gro, a lot of usefull information is mentioned here.

[jerrytheplater]

Steve

Who is/was Iann? I just went back to the "Coir Anyone" article you quoted when posting about Ammonium and Nitrate. He sounds pretty knowledgeable.

And I have used Coir but I never rinsed it at first, at least 10 years ago. What I'm using now has been rinsed since the package said to do so.

[Steve Johnson]

Steve

Who is/was Iann? I just went back to the "Coir Anyone" article you quoted when posting about Ammonium and Nitrate. He sounds pretty knowledgeable.

And I have used Coir but I never rinsed it at first, at least 10 years ago. What I'm using now has been rinsed since the package said to do so.

Iann is an expert grower who used to be more active on the forum. He lives in the UK, and you'll find his more current activity on the BCSS forum. (If he's not a chemist by trade, he seems to have a good knowledge of chemistry regardless.) While I do respect his expertise, I'm afraid that he wasn't a good teacher when it came to explaining how fertilizers work and how we should approach the matter. MikeInOz has proven himself to be much better with that, hence my reason for posting the sticky in a "pay it forward" effort to share what we've learned from him. You would think all this is common knowledge in the cactus and succulent community at large, but from what I've seen online and visiting local cactus clubs, apparently it's not.

I'm glad you mentioned Coir. The problem with soil-based mixes is that organic material in the soil can harbor plant pathogens leading to the possibility of rot and fungal infections. Even though Coir is organic, it behaves like an inorganic material. For growers in arid climates who can't use a hydroponic mix because it dries out to quickly, Coir may be a better soil substitute for the water retention they need in the mix. Haven't used it myself, but I've heard some good things about it from experienced growers who do.

[MikeInOz]

Steve

Who is/was Iann? I just went back to the "Coir Anyone" article you quoted when posting about Ammonium and Nitrate. He sounds pretty knowledgeable.

And I have used Coir but I never rinsed it at first, at least 10 years ago. What I'm using now has been rinsed since the package said to do so.

Iann is an expert grower who used to be more active on the forum. He lives in the UK, and you'll find his more current activity on the BCSS forum. (If he's not a chemist by trade, he seems to have a good knowledge of chemistry regardless.) While I do respect his expertise, I'm afraid that he wasn't a good teacher when it came to explaining how fertilizers work and how we should approach the matter. MikeInOz has proven himself to be much better with that, hence my reason for posting the sticky in a "pay it forward" effort to share what we've learned from him. You would think all this is common knowledge in the cactus and succulent community at large, but from what I've seen online and visiting local cactus clubs, apparently it's not.

I'm glad you mentioned Coir. The problem with soil-based mixes is that organic material in the soil can harbor plant pathogens leading to the possibility of rot and fungal infections. Even though Coir is organic, it behaves like an inorganic material. For growers in arid climates who can't use a hydroponic mix because it dries out to quickly, Coir may be a better soil substitute for the water retention they need in the mix. Haven't used it myself, but I've heard some good things about it from experienced growers who do.

I wouldn't use coir unless I absolutely had nothing else to use. And probably still wouldn't. It has many problems. 1, It is often high in chloride, this can be mitigated by rinsing several times. 2, It has very low S and Ca and very high K. So much so that it can cause Mg deficiencies unless it is amended. Soaking in CaSo4 or MgSo4 and CaNo3 after rinsing can help. 3, Orchid growers were initially told that Coconut was the medium to end the use of all other mediums and went ahead and used it at full throttle. What did they find? Most had great results for a start and then found all kinds of deficiencies showing up later, severe chlorosis, death of roots and death of the entire plant in many cases. 3, Fungal mycelium LOVES coir unless it is completely consumed by composting. It thrives in it and if it gets a foot hold, the entire root ball can become choked with white mold and dead roots. Fungus tends to proliferate in dry, acidic conditions rather than moist alkaline ones where bacteria usually dominates. 4, It should have Fe and Cu added to it. 5, It is sometimes prepared from green husks and can contain unwanted plant hormones. Having said all that some people say they have used it with success but I think we should be aware of it's possible problems. It is interesting to note that some commercial Dutch nurseries said they never want to have to see or deal with coir products again. If you want to use an organic component in your mix, a far superior product can be easily - if somewhat slowly - made a year in advance by using readily available products such and leaves, cow manure and sawdust or shredded garden clippings composted well and matured moist over a long time then dried, screened and stored for later use. Or if you have access to genuine cow manure (luckily I have from a farmer next door) you can age that and use it. Another option is to use a high quality composted pine bark as the organic fraction of your mix. All these are far superior in every way to coir.

[Steve Johnson]

Hi Mike,

Thanks for warning us about the problems with Coir. To be honest, I haven't been in contact with local growers since the COVID-19 pandemic, but it would be interesting to find out if the ones using Coir have backed away from it due to the problems you mentioned. Just out of curiosity, I checked out gardening websites that discuss various types of soil-less mix, and oddly enough, they tout Coir as an ingredient. Plenty of gardening myths and misinformation on the Web, so I wonder if Coir could be part of it.

[MikeInOz]

Hi Mike,

Thanks for warning us about the problems with Coir. To be honest, I haven't been in contact with local growers since the COVID-19 pandemic, but it would be interesting to find out if the ones using Coir have backed away from it due to the problems you mentioned. Just out of curiosity, I checked out gardening websites that discuss various types of soil-less mix, and oddly enough, they tout Coir as an ingredient. Plenty of gardening myths and misinformation on the Web, so I wonder if Coir could be part of it.

Coir dust is used successfully in mixes for bedding plants and general mixes where it is fed heavily (EC is high) and it is kept moist, but for mixes which dry completely you can have the troubles I mentioned. As long as the Ca, Mg, and S is balanced with it's high K, and the chloride is leached out it works ok. It actually has very good properties like high AFP and wettability. But because it is made from raw un-composted material, and some batches are exceptionally bad, when something goes wrong it goes wrong spectacularly. Another problem is that it holds water for such a long time, you might think your mix is dry and needs water when it doesn't. I cannot understand why cacti growers would use it.

[keith]

I wouldn't use coir unless I absolutely had nothing else to use" I still wouldn't use it . Did a experiment with mint plants its not for me.

I like regular loam better than any organic bought in a bag for cactus. Mixed with Pumice or similar course material .

[Steve Johnson]

Another problem [with Coir] is that it holds water for such a long time, you might think your mix is dry and needs water when it doesn't. I cannot understand why cacti growers would use it.

I can't remember where I heard this from (think it might've been iann), but it sounds like the same problem with peat -- takes forever to wet, and when it's wet, it takes forever to dry out. I wouldn't use peat in a cactus mix myself, but I'm wondering if there's a trick to it for people who do well with peat in the mix. This info could come in handy for some of our other members.

I like regular loam better than any organic bought in a bag for cactus. Mixed with Pumice or similar course material.

By "regular loam", do you mean sandy loam? Reason I ask is that sandy loam soils are perfect as the soil component in cactus mixes, but clay loams are not so good for cactus roots under pot cultivation. I should also mention that pure loams are inorganic mineral soils, although I don't know if such a thing exists in the real world.

Keith, where do you get your loam? If it's a place that can sell me a 10 or 20 pound bag, that would be enough to last me a good long time. I'll trust your loam over the so-called "cactus mixes" we see on Amazon, and I'm out of the only decent mix I found at the California Cactus Center in June 2011.

[MikeInOz]

Another problem [with Coir] is that it holds water for such a long time, you might think your mix is dry and needs water when it doesn't. I cannot understand why cacti growers would use it.

I can't remember where I heard this from (think it might've been iann), but it sounds like the same problem with peat -- takes forever to wet, and when it's wet, it takes forever to dry out. I wouldn't use peat in a cactus mix myself, but I'm wondering if there's a trick to it for people who do well with peat in the mix. This info could come in handy for some of our other members.

I almost always use sphagnum peat in mixes to regulate the pH. I have both Canadian and Estonian peat. The Canadian is coarser but both are useable. I screen out the dust under 1 mm and particles over 3 or 4 mm and add it to my mix last as mixing can reduce the particles down again. It is important to mix it in dry. I use about 10% or so. I also add a pinch of copper sulphate and some Iron sulphate as peat holds copper very tightly. Lime (Limestone ''sand'') is not added unless I am planting limestone species or the other components of the mix are all acidic - which is unlikely.

[MikeInOz]

By "regular loam", do you mean sandy loam? Reason I ask is that sandy loam soils are perfect as the soil component in cactus mixes, but clay loams are not so good for cactus roots under pot cultivation. I should also mention that pure loams are inorganic mineral soils, although I don't know if such a thing exists in the real world.

Keith, where do you get your loam? If it's a place that can sell me a 10 or 20 pound bag, that would be enough to last me a good long time. I'll trust your loam over the so-called "cactus mixes" we see on Amazon, and I'm out of the only decent mix I found at the California Cactus Center in June 2011.

I recently have been using kanuma and hard akadama (both Japanese clays which do not break down with watering) as a 30% component in the mix and the cacti seem to thrive in them. They are expensive but for a medium sized collection, they are recommended.
https://www.google.com/search?q=kanuma+ ... 3&dpr=1.25

[keith]

My loam is sandy loam from the Mojave desert , I used to get it from AZ when I lived there and now get it from desert near Randsburg. Its sandy and probably mostly mineral.
Next time I'm out I'll source a bucket for you if you want, I need to test it. I have way more time now because my ex-employer just eliminated my position. I'm retired now .

[Steve Johnson]

I have way more time now because my ex-employer just eliminated my position. I'm retired now .

Good for you, Keith!

My loam is sandy loam from the Mojave desert , I used to get it from AZ when I lived there and now get it from desert near Randsburg. Its sandy and probably mostly mineral.
Next time I'm out I'll source a bucket for you if you want, I need to test it.

I have only 4 cacti that need soil for a 50/50 pumice-soil mix -- 2 Tephros (inermis and papyracanthus) and 2 Eriosyce senilis. The sandy loam from Randsburg sounds great, although as I said earlier, only 10 or 20 pounds would last me a good long time. I won't be doing any repotting until spring anyway, so if you can get the loam for me before the end of May, I'd surely appreciate it. Just send me a PM whenever you have it. Good opportunity to visit with you and see your collection too!

Mike -- I tried growing the Tephros in a hydroponic mix (that was 2012), but their thin scraggly roots would support it. Once I moved them into the 50/50 pumice-soil mix, they finally started growing new segments in 2013 and they've been growing more segments ever since. The same mix for E. senilis was recommended by iann, and both of mine are loving it too. Funny thing about papyracanthus...

My "paper spine" Tephro had a bad habit of dropping segments. Other growers told me that's the way the species behaves, so I didn't think anything of it. After 2 years of Potassium sulfate supplement and a growing season with the CalMag added this year, the "paper spine" grew not 1, not 2, not 3, but 4 new segments. No sign of segments dropping yet -- if the plant stays intact with more new segments growing this year, I think it may be due to the higher Potassium and CalMag.