The Cal-Mag of my dreams?

[Aztekium123]

This discussion is valuable

[SDK1]

Steve and Jerry,

If the goal is more a bit more potassium, another option is potassium silicate. It also provides the benefit of including the trace element, silicon, not present in DGs typical formula. Potassium silicate will raise the pH rather noticeably but it's easily managed by letting the water rest for awhile and acidify or just doing it yourself with any number of products.

Steve, I was wondering why do you go for the 7-7-7 formula rather than the 9-3-6 offered by DG? Any particular reason or just comfort/convenience?

Thanks,

Johnny

[Steve Johnson]

Steve, I was wondering why do you go for the 7-7-7 formula rather than the 9-3-6 offered by DG? Any particular reason or just comfort/convenience?

Comfort and convenience have nothing to do with it, so this gives you all the details on what I'm doing and why:

viewtopic.php?p=393985#p393985

When you read through the post, it "fleshes out" the information I learned from MikeInOz, and it'll provide some context to what you saw in the post that started this thread. Just to follow up there, I'll be starting a 2022 end-of-summer review at my Member Blogs thread. When I do, we can see the "before and after" improvements with 2 years of Potassium sulfate supplementation and a year of the additional Cal-Mag fert.

Also, you might want to do this:

viewtopic.php?t=43820

By the way -- in case you were wondering, the correct NPK ratios I go by come directly from Mike. Unlike other fert "experts" I've seen elsewhere on the Web, he really does know what he's talking about.

[ohugal]

If I would look for a Cal-Mag supplement, what should I pay attention to? No nitrogen level, 4:1 calcium magnesium, … Something else?
I’ve looked at some products being sold at the website where I buy my General Hydrophonics fertilizer. A few mention to use the supplement only with soft or RO water.

[jerrytheplater]

I’ve looked at some products being sold at the website where I buy my General Hydrophonics fertilizer. A few mention to use the supplement only with soft or RO water.

The reason for the soft water is to prevent the carbonates in most tap water from reacting with the Ca and Mg in the fertilizer and precipitating out of solution. Rain water works too.

[Steve Johnson]

Rainwater is best for growers who can store enough to meet the yearly watering needs of their collections. For growers who can't, RO may be fine, but RO systems waste a lot of water. I've been acidifying my tap water with 5% white vinegar for over 10 years, and I can tell y'all that it works incredibly well.
I posted a presentation on the subject available here:

viewtopic.php?t=43525

Disregard the first member's response -- a reliable pH meter like the one I'm using really is the best way to measure the water's pH.

[Download]

Interesting to see you people buying premixed soluble fertiliser like that. It seems expensive.

I mix up my own. I paid about $70 for a 20kg bag of potassium nitrate a few years back, then I throw in monopotassium phosphate and soluble trace elements, then I boil the whole thing up and use a coffee filter to remove any insoluble bits. I don't add calcium as I add chicken grit made from sea-shells to all of my potting mix. I still have about half a bag of KNO3 (though I need more MKP), and I've only had to spend ~$150 on fertiliser over several years.

[jerrytheplater]

Interesting to see you people buying premixed soluble fertiliser like that. It seems expensive.

I mix up my own. I paid about $70 for a 20kg bag of potassium nitrate a few years back, then I throw in monopotassium phosphate and soluble trace elements, then I boil the whole thing up and use a coffee filter to remove any insoluble bits. I don't add calcium as I add chicken grit made from sea-shells to all of my potting mix. I still have about half a bag of KNO3 (though I need more MKP), and I've only had to spend ~$150 on fertiliser over several years.

I buy bulk fertilizers like you do, but it is for repackaging and selling to members of my Aquatic Gardening club. My friend is a commercial greenhouse owner and lets me buy using his account. Greenhouse grade Potassium Nitrate-KNO3, Mono Potassium Phosphate-KH2PO4, and Potassium Sulfate-K2SO4. I also buy a chelated micronutrient mix called Plantex NutriTrace CSM- https://www.plantprod.com/product/plant ... trace-csm/

Boiling is not needed to mix. In fact, if you have Boron in your mix, you will boil it off. If you are seeing any solids left, it most likely will be Calcium or Magnesium Phosphates from your mixing water. Forget what I said if you are using rainwater or other low mineral water. Then it might be impurities in your fertilizers.

I still use soluble fertilizers, even though I have several lifetimes of dry fertilizers. It is easier to measure out liquids and dilute than to weigh out without a proper balance.

[ohugal]

Interesting to see you people buying premixed soluble fertiliser like that. It seems expensive.

I mix up my own. I paid about $70 for a 20kg bag of potassium nitrate a few years back, then I throw in monopotassium phosphate and soluble trace elements, then I boil the whole thing up and use a coffee filter to remove any insoluble bits. I don't add calcium as I add chicken grit made from sea-shells to all of my potting mix. I still have about half a bag of KNO3 (though I need more MKP), and I've only had to spend ~$150 on fertiliser over several years.

It's very good if you have the knowledge to mix up your own low cost proper fertilizer, but not everyone has the technical 'baggage'. Hence the existence of consumer products... It's not that weird.
If you have a small collection, you're not really inclined to compose your own fertilizer in bulk. I've come across recipes for 'homemade' fertilizers in plant books, but I think of these as things of the past. Perhaps not rightly so.
I apologize for diverting the conversation, but one of my other past times is tea. I mainly drink loose tea and not tea bags. Tea bags are basically a scam, but are very practical. I understand why their use is so widespread.
Anyways, I've invested a lot of time in following up on the fertilizer advice from Steve, Jerry and others on the forum, so I'm going to stick to that for a while.
Still on the lookout for a good CalMag supplement and otherwise I'll just add some sea shells to the mix.

[Steve Johnson]

Interesting to see you people buying premixed soluble fertiliser like that. It seems expensive.

I mix up my own. I paid about $70 for a 20kg bag of potassium nitrate a few years back, then I throw in monopotassium phosphate and soluble trace elements, then I boil the whole thing up and use a coffee filter to remove any insoluble bits. I don't add calcium as I add chicken grit made from sea-shells to all of my potting mix. I still have about half a bag of KNO3 (though I need more MKP), and I've only had to spend ~$150 on fertiliser over several years.

No direspect re. what you're doing, but I'll take my fertilizer advice from MikeInOz since he knows a lot more about ferts than I'd ever know on my own. If the premixed ferts I use seem expensive, they're worth every penny.

Do you remember seeing this?

viewtopic.php?p=382867#p382867

Unfortunately I can't get the Osmocote slow-release fert Mike has been using (with excellent results, by the way), but you can. If it's worth your consideration, the Osmocote might also be more cost-effective depending on the size of your collection.

[Download]

Interesting to see you people buying premixed soluble fertiliser like that. It seems expensive.

I mix up my own. I paid about $70 for a 20kg bag of potassium nitrate a few years back, then I throw in monopotassium phosphate and soluble trace elements, then I boil the whole thing up and use a coffee filter to remove any insoluble bits. I don't add calcium as I add chicken grit made from sea-shells to all of my potting mix. I still have about half a bag of KNO3 (though I need more MKP), and I've only had to spend ~$150 on fertiliser over several years.

No direspect re. what you're doing, but I'll take my fertilizer advice from MikeInOz since he knows a lot more about ferts than I'd ever know on my own. If the premixed ferts I use seem expensive, they're worth every penny.

Do you remember seeing this?

viewtopic.php?p=382867#p382867

Unfortunately I can't get the Osmocote slow-release fert Mike has been using (with excellent results, by the way), but you can. If it's worth your consideration, the Osmocote might also be more cost-effective depending on the size of your collection.

It's not clear to me what you are trying to say.

[Steve Johnson]

It's not clear to me what you are trying to say.

Okay, then let me clarify...

As I've stated many times before, MikeInOz is a professional horticulturalist with a deep knowledge of cacti and succulents -- the best explainer of ferts I've ever seen. Here are the key lessons I learned from him:

• How NPK values are reported on the label by fert manufacturers in different countries. In Australia P and K are reported as elemental values, everywhere else it's P2O5 and K2O. Since the oxygen in P2O5 and K2O has no nutrient value, we're concerned only with knowing the amount of elemental P and K in the fert. In my case, the Dyna-Gro 7-7-7 I'm using is in fact 7-3.05-5.81, so those are the actual NPK values.

• For cacti and succulents, the ideal NPK ratio in a well-balanced fert is 1:0.4:1.5.

When I put those 2 lessons together, Mike confirmed that the 7-7-7's balance between N and P is as close to perfect as we can get. He has also been quite aware of the fert's chemical analysis:



All I had to do was figure out how much Potassium sulfate I would need so that K is 1.5 times higher than N in my dilute 7-7-7 watering solution (I've discussed those details in previous posts). He also said that there's no such thing as too much Calcium, hence my reason for supplementing the watering solution with a good Nitrogen-free CalMag fert that doubles the amount of Ca and Mg provided by the 7-7-7. End result -- a well-balanced and comprehensive spectrum of all the nutrients going into my cacti.

Does your "mix your own" fert match that nutrient profile? What I'm trying to say is that if it doesn't, you could do better with the Osmocote Cacti & Succulents slow-release fert Mike uses:

P1140349.JPG (96.71 KiB) Viewed 1192 times

You're able to buy the Osmocote C&S formulation since you and he both live in Australia, so I was just giving you an alternative to consider. If you're not interested, that's your choice.

Going back to that comment of yours:

Interesting to see you people buying premixed soluble fertiliser like that. It seems expensive.

First of all, "you people" is being dismissive of the fact that us people may have legitimate well-thought reasons for doing what we're doing. Regarding the costs involved, "expensive" is a relative term -- what seems expensive to you isn't necessarily expensive to other members. As for me, the 7-7-7, Potassium sulfate supplement, and CalMag fert I use give me a lot of "bang for the buck" given the wonderful growing improvements I see. Like I said before, they're worth every penny.

[keith]

'Calcium must be balanced with Magnesium, and the ideal Ca-to-Mg ratio is 4:1.' Copied from another post and below

from the picture I see CA 1.2% and MN 3.4 % is that backwards the ideal ratio ?

[ohugal]

I’ve looked at some products being sold at the website where I buy my General Hydrophonics fertilizer. A few mention to use the supplement only with soft or RO water.

The reason for the soft water is to prevent the carbonates in most tap water from reacting with the Ca and Mg in the fertilizer and precipitating out of solution. Rain water works too.

I've checked the website of my tapwater 'supplier'. The water that comes out of my tap is semi-hard. I acidify my water to a pH of 5,5. pH and hardness are not the same, but are connected as I understand it. I've recently purchased the Flora Bloom and Flora Micro from General Hydrophonics (in Europa it's called Terra Aquatica). The Flora Micro has 2 versions, one for soft and one for hard water. I did not know this. The website I got it from was not very informative and I purchased the soft water version. According to the website, this version already has enough calcium and a calcium supplement is not needed. No mention of magnesium at first sight, but I will double check.
Regardless of the preference of fertilizing discussed here, I enjoy learning all this stuff.

[jerrytheplater]

I’ve looked at some products being sold at the website where I buy my General Hydrophonics fertilizer. A few mention to use the supplement only with soft or RO water.

The reason for the soft water is to prevent the carbonates in most tap water from reacting with the Ca and Mg in the fertilizer and precipitating out of solution. Rain water works too.

I've checked the website of my tapwater 'supplier'. The water that comes out of my tap is semi-hard. I acidify my water to a pH of 5,5. pH and hardness are not the same, but are connected as I understand it. I've recently purchased the Flora Bloom and Flora Micro from General Hydrophonics (in Europa it's called Terra Aquatica). The Flora Micro has 2 versions, one for soft and one for hard water. I did not know this. The website I got it from was not very informative and I purchased the soft water version. According to the website, this version already has enough calcium and a calcium supplement is not needed. No mention of magnesium at first sight, but I will double check.
Regardless of the preference of fertilizing discussed here, I enjoy learning all this stuff.

I enjoy it too!!!

When you acidify your water you are neutralizing the carbonates it contains to produce CO2 gas. This hardness can also be called Alkalinity. There is another hardness called General Hardness which is dependent on the concentration of Calcium and Magnesium and other less common divalent cations. That hardness does not change with pH. There are graphs which will show you the concentrations of carbonate, bicarbonate and carbonic ions in water vs. pH.

Is there a web address for the seller of your fertilizer?