The Cal-Mag of my dreams?

[jerrytheplater]

I looked at the site and I could not find anything either Oscar. I thought the product data sheet would show it. Nada. My guess, and only my guess: they dissolved Dolomitic limestone in water, added humates and filtered it/or decanted it to removed the undissolved Dolomitic limestone, dropped the pH to remove the carbonates and bottled it up. The humates would latch onto the soluble Ca and Mg.

[Steve Johnson]

I looked at the site and I could not find anything either Oscar. I thought the product data sheet would show it. Nada.

Maybe it's because we can get a guaranteed analysis only in the US. From mountain lion garden supply:

Biobizz_CalMag_guaranteed_analysis.jpg (167.73 KiB) Viewed 2894 times

I'm pretty sure this guaranteed analysis would apply worldwide, although why it's not reported in the European market is beyond me. Regarding the product's Ca-Mg ratio, here's a quote from Mike in my "Fertilizers explained" thread:

I'd love to know where these values (the ratios) are sourced from.

In my book on growing media the following quote - ''Media in which plant growth is excellent tends to have extractable Ca/Mg ratios of about 3 to 4''.
Meaning - Calcium 3-4 times that of Magnesium. It is not critical but ''where high levels of K are applied the ratio should be lower rather than higher. A Ca/Mg of 2 rather than 5''.
''High levels of K'' could mean a K/N ratio of 2 or more. Given all that, the ''3 to 4'' seems to be a pretty good number for us

Oscar -- assuming that you're using the Terra Aquatica fertilizers and supplements I laid out for you, the K/N ratio in your watering solution is 1.5, so I think the Biobizz CalMag should be fine. The only thing you'll need to figure out is the proper dilution, but I can help you there once I run the calculations diluting in mL/L.

[Steve Johnson]

And there you go -- 0.5 mL Biobizz/L. That's roughly equivalent to the 1/4 tsp. TPS CalMag I add per gallon of my watering solution. Although Mike has said "there's no such thing as too much calcium", I tend to be a little more cautious about it. If you don't see any reason to be as cautious, you can go with 1 mL/L. For your consideration, here's something else he said:

The only thing I'm concerned about is the fact that you have the same amount of N and Ca (even though your Ca-to-Mg ratio is good), seems like the Ca would be too high in relation to N.

As long as it doesn't interfere with pH, (nutrient uptake), calcium is not a problem. There's no such thing as Ca toxicity.

Oscar, the quote comes from your "watering & fertilizing for mineral soil mix" thread. The only thing that would interfere with nutrient uptake is if the roots of your cacti are subjected to a pH substantially below 6, so if you keep the pH in the 6.0-7.0 range, maybe there isn't a need to be so cautious about the amount of Biobizz you're diluting.

[ohugal]

Hey Jerry & Steve,

Thank you for the information.
Unfortunately the labels of fertilizers here are quite brief. Biobizz wrote me just now they don't know the calcium/magnesium ratio. I'm not sure if I'm going to purchase it just yet. I added gypsum and limestone at the beginning of the growing season. I kept looking for a nitrogen-free calcium/magnesium supplement, because I find adding limestone and gypsum a bit tedious. I prefer a liquid supplement, that way I don't have to keep track of which plant got what and when.
I don't know whether lockout will be an issue. My fertilizer solution has a pH of 6,67. After watering the soil the pH is 4,9 and goes to 6,3 after 30 hours. This experiment was conducted without a plant in the soil. I must say I did not do any additional pH measuring this summer. Perhaps I'll measure pH again this weekend.
For my standards the growing season was successfull compared to previous years. I had some losses, but those were weakened plants from the past years. I'm curious and excited for the summer of 2024!

[Steve Johnson]

Biobizz wrote me just now they don't know the calcium/magnesium ratio. I'm not sure if I'm going to purchase it just yet. I added gypsum and limestone at the beginning of the growing season. I kept looking for a nitrogen-free calcium/magnesium supplement, because I find adding limestone and gypsum a bit tedious. I prefer a liquid supplement, that way I don't have to keep track of which plant got what and when.

I agree with you on the limestone and gypsum -- not only tedious, but difficult to get it right for those of us who don't have the level of expertise people like MikeInOz have.

Go back and look at the Biobizz guaranteed analysis label I just showed you, then note the following: "Manufactured and guaranteed by Biobizz Worldwide SL" [my emphasis]. I'm 99% sure that the guaranteed analysis applies everywhere, although it'd be good to make it 100%. If you have been writing to a local Biobizz distributor, go straight to the source and contact Biobizz Worldwide SL at info@biobizz.com. If they verify the guaranteed analysis, go ahead and buy it. You might also want to let them know that their European distributor is falling down on the job -- failure to provide a guaranteed analysis to their customers is IMO unacceptable.

I don't know whether lockout will be an issue. My fertilizer solution has a pH of 6,67. After watering the soil the pH is 4,9 and goes to 6,3 after 30 hours.

Lockout in the watering solution -- no, it won't happen. I'd be more concerned about nutrient leaching while the pH in the watered soil is substantially below 6.0. This pH/nutrient availability chart give us some insight:

pH_nutrient_ availability_ chart01.jpg (81.4 KiB) Viewed 2874 times

We're talking about 24 hours going from a pH of 4.9 to 6.0, so I don't think your cacti would lose much in the way of nutrients. But the freshly-watered soil starting at 6.0 would be better. That initial 4.9 number doesn't seem right, so please remind me about what's in your mix -- ingredients and proportions.

[ohugal]

I have been emailing with info@biobizz.com and there's not other email address. So I don't think I will make progress on that front.
My substrate consists of 4 parts grit (small stones, approx. 2/3mm), 5 parts pumice (no dust) and 1 part loam (not sand, more on the clayish side). I honestly think it's the loam which might cause the initial low pH. But that's without the plant. My substrate dries out fairly quick and the loam sort of holds the other components together but crumbles easily when you pinch it. I might also do a test over the weekend without the loam. I have reliable soil pH meter, so it's not that much work. I had some species which started growing rather late, e.g. Echinopsis oxygona and Gymnocalycium calochlorum. For Echinopsis pachanoi and Agave victoria-reginae I think the mix is too gritty.
Oh, I forgot... I did a pH test on the substrate with distilled water, pH was 6 after a 1 hour soak. So, perhaps it's how the soil reacts with the fertilizer solution causing a low starting pH. pH of fertilizer solution is 6,67. All tests were done on the same day and I was pretty thorough.

Ooh, I only noticed it now, thank you for the Biobizz CalMag label! I should check U.S. sites in the future and not only E.U. stores.

[Steve Johnson]

Ooh, I only noticed it now, thank you for the Biobizz CalMag label! I should check U.S. sites in the future and not only E.U. stores.

Yes, we got lucky by virtue of the fact that Biobizz is being sold in the US -- guaranteed analysis disclosed on fertilizers is required by law. If the EU isn't doing this, I'm kinda surprised.

My substrate consists of 4 parts grit (small stones, approx. 2/3mm), 5 parts pumice (no dust) and 1 part loam (not sand, more on the clayish side). I honestly think it's the loam which might cause the initial low pH. But that's without the plant. My substrate dries out fairly quick and the loam sort of holds the other components together but crumbles easily when you pinch it. I might also do a test over the weekend without the loam. I have reliable soil pH meter, so it's not that much work. I had some species which started growing rather late, e.g. Echinopsis oxygona and Gymnocalycium calochlorum. For Echinopsis pachanoi and Agave victoria-reginae I think the mix is too gritty.

Pure loam is an inorganic mineral soil, so I think what you really have is topsoil (loam plus organic material) AKA humus. Your test of the mix without soil is a good idea, and I do think soil is the reason why your initial pH is so low. Going from 4.9 up to a higher number is known as "pH rebound", and I don't know if rebounding from 4.9 to 6.3 in 30 hours is necessarily a problem unless it keeps going up to 7.5 or higher by the time your mix dries out. That's something you'll have to test. Of course a more stable pH going from wet to dry would be nice, although I don't know how one goes about doing it. Not sure if this is even an issue, but I'll investigate further.

[Steve Johnson]

Hi Oscar,

I sent a PM to Mike regarding the pH 4.9-6.3 rebound -- you have nothing to worry about, so keep doing what you're doing and add the Biobizz CalMag to your fertilizer regimen once you receive it. Re. what I just said about humus, I need to get my facts straight:

https://en.wikipedia.org/wiki/Humus

I think the soil you're using in your mix is topsoil.

[ohugal]

Hey Steve,

Thank you again for figuring this out. Perhaps some European members were reading this and know there is a suitable CalMag supplement available for them.

I once did a test on the loam I have to determine the composition. My findings were posted on the forum (somewhere). I think it was low in sand and high in clay particles with practically no organic matter present. I will see in a few years whether the substrate is good for my plants or not.

A question out of curiosity, is it possible for a certain component/material (e.g. clay) to wick moisture from the surrounding air?

[Steve Johnson]

Hey Steve,

Thank you again for figuring this out. Perhaps some European members were reading this and know there is a suitable CalMag supplement available for them.

Always glad to help!

A question out of curiosity, is it possible for a certain component/material (e.g. clay) to wick moisture from the surrounding air?

I believe so, but I don't think it'll go below the surface of the pot.

[jerrytheplater]

A question out of curiosity, is it possible for a certain component/material (e.g. clay) to wick moisture from the surrounding air?

I purchase clay for use by potter's at a local pottery supply store. It is sold as a dry powder, or you can order it mixed up and ready to use if you are a potter. Many different types of clay to choose from. I use it when setting up an aquarium for growing aquatic plants.

I have mixed that clay with other components and water to make a very plastic clay mixture similar to what my kids used to play with. I've let this mixture dry out by letting it sit uncovered. It dries to a rock hard, brittle mass.

If the clay would absorb water from the humidity in the air, it would not dry out like it does. We have plenty of humidity here in NJ. Clay will absorb water in the soil and hold on to it for a very long time. It gets between the microscopic layers of clay particles and is very hard to dry out. But, it will over time and form a cracked soil surface in very clay rich soils.

I don't see many such soils in my area, although the area around Trenton, NJ was known for pottery in the past. https://potteriesoftrentonsociety.org/

Bricks were made in the Woodbridge area. So there are clay deposits in my state. https://www.hmdb.org/m.asp?m=126839

[Steve Johnson]

We have plenty of humidity here in NJ. Clay will absorb water in the soil and hold on to it for a very long time. It gets between the microscopic layers of clay particles and is very hard to dry out. But, it will over time and form a cracked soil surface in very clay rich soils.

You brought up a good point to consider regarding what Oscar just said:

I once did a test on the loam I have to determine the composition. My findings were posted on the forum (somewhere). I think it was low in sand and high in clay particles with practically no organic matter present.

Oscar, you might want to check that:

The sandy loam, I have not tested it to determine what type is. I purchased it as sandy loam.

Here's a good way for applying a DIY soil texture analysis to test your loam:

https://hgic.clemson.edu/factsheet/soil ... -jar-test/

If you run the test and find that the loam has too much clay, would that be a problem? In your 90% mineral/10% loam mix, I don't think so, although I can't be sure. But in a 50% mineral/50% loam mix (like what I'm recommending for regrowing the roots of your Eriosyce senilis), a high-clay loam would be a problem IMO. Unfortunately I don't have any recommendations on what you can do about it.

[Steve Johnson]

Okay, here's the soil sample from the Clemson University website together with a reading of the soil texture pyramid:

Clemson_University_soil_analysis.jpg (114.17 KiB) Viewed 2787 times

The loam in the above sample is 59% sand, 35% silt, and 6% clay. Draw a line from 59% sand to 35% silt, then draw a horizontal line on 6% clay. The intersection of the 2 lines shows that the loam is sandy loam. When you run the "jar test" per Clemson University's instructions, you'll know how to read and analyze your soil using the pyramid. (Not to be confused with "pyramid schemes"! )

[ohugal]

The loam I have is rich in clay, which is something I tend to forget. I did a sediment test already a while ago.
It's a bit of a mystery to me how a soil with a pH 6 in combination with a fertilizer solution pH 6,67 results in a soil pH 4,9 (1 hour soak). I'm watering my cacti tomorrow. It's quite sunny and warm again. So perhaps a good time to double check pH values again. If the pH rebound is not an issue, I will continue to use loam. It gently holds the soil together.
I did not use the loam as part of the substrate for rerooting the Eriosyce senilis. For that I used sieved pine bark. I'm not entirely happy with the structure. Perhaps I was a bit too hasty with the sieving process. I have two Tephrocacti which do great in the mineral mix.
I asked about the wicking capacity of clay for example, because last year I had a Leuchtenbergia with stem rot. I am a 100% sure I didn't water it in previous months. The soil was slightly damp. The substrate is not what I'm using now, but a mix I purchased from a seller. I don't know the exact composition. It could also have been a leak in the glass roof of the spot where they hibernate.

p.s. I couldn't help myself, but I checked and the E. senilis is already developing new roots!

[Steve Johnson]

I couldn't help myself, but I checked and the E. senilis is already developing new roots!

Woo hoo!

I did not use the loam as part of the substrate for rerooting the Eriosyce senilis. For that I used sieved pine bark. I'm not entirely happy with the structure.

Can you post a photo of the mix? It'll be easier for me to see what its structure looks like before I come to any conclusions. If the E. senilis is already growing new roots, IMO there's nothing wrong with the mix's structure, but a photo would help for evaluation.