Cal/Mag Deficiency Organic Soil

Harry Bonanza

Well-Known Member
Hello Growers. Discovered a cal/mag deficiency in a couple of my plants. Media is organic potting mix with Gaia Green 4-4-4 dry amendments. They’ve had a couple compost teas and there was a late up-pot. I’ve top dressed some lime but wondering what would help deliver calcium a little quicker. I’m a few days away from my supply run so cal/mag is not an option. I’ve read molasses has calcium and it was in the tea so I’m hoping I’m already on the road to recovery but looking for ideas. Most answers here involve a run to the shop
 

Johiem

Well-Known Member
Eggshells. Dry them, bake for 20 min @200°f, crush them, using a non-nonstick pot boil about a half cup of shells in 2 cups of distilled water till half if the water remains, stirring frequently. Let it cool and give her the water. Hell, you can dump the entire contents, shells and all. The water will give her an immediate CA boost and the shells will amend the soil with CA as they degrade further. I pulled 388ppm of CA to add to my hydro girls. If it is a mag issue I've read Epsom salts have mag, I just don't know how much to give them safely.
 

Harry Bonanza

Well-Known Member
Are you sure it’s a cal mag deficiency ?
I’m not %100 but it’s presenting as the same issue I had last year with a lack of lime. It also presents somewhat like a potassium toxicity. I’ll grab a couple pics. There’s a bunch of factors. New LED light sped this up, I had a cover crop that was a bit thick in some pots before up-pots maybe too much organic material, and had some fungus gnats but they appear to be under control
 

Harry Bonanza

Well-Known Member
Eggshells. Dry them, bake for 20 min @200°f, crush them, using a non-nonstick pot boil about a half cup of shells in 2 cups of distilled water till half if the water remains, stirring frequently. Let it cool and give her the water. Hell, you can dump the entire contents, shells and all. The water will give her an immediate CA boost and the shells will amend the soil with CA as they degrade further. I pulled 388ppm of CA to add to my hydro girls. If it is a mag issue I've read Epsom salts have mag, I just don't know how much to give them safely.
That’s awesome thank you!! I have ground eggshells for my worm bin. This will be tonight’s project.
 

SneakyBob

Well-Known Member
Can make some WCA/ water soluble calcium using egg shells or the oyster shell flour and vinegar. I made some but haven't really needed to use it often because i use a lot of OSF in my soil.
 

Harry Bonanza

Well-Known Member
Your lime will probably do the trick over a few days if it's powder. The web says it takes 2 years to work but plants says otherwise lol
That is some mind easing info there thank you. Confident things will balance out but these ones I was hoping to flip into flower for a mid summer harvest. This quarantine has put a real beating on my stash lol
 

PadawanWarrior

Well-Known Member
I didn’t bother replacing my pen as PH really shouldn’t be an issue once things balance out but I suspect if anything it would be a touch high. No synthetic nutes and my tap water usually creeps up towards 8.
Pics would help. And even though you're growing organically, pH still matters. Microbes can only buffer the pH so much. I finally ordered the BlueLab soil pen and couldn't be happier.

But if you really need Ca and want to raise the soil pH, oyster shell flour like @Budzbuddha mentioned is what I'd use.
 

Harry Bonanza

Well-Known Member
Pics would help. And even though you're growing organically, pH still matters. Microbes can only buffer the pH so much. I finally ordered the BlueLab soil pen and couldn't be happier.

But if you really need Ca and want to raise the soil pH, oyster shell flour like @Budzbuddha mentioned is what I'd use.
I looked at the Blue Lab a while back after seeing it used on a YouTube channel. Until then I didn’t trust any of the store bought pens but this ones seems to work and I do trust anything blue lab makes. It makes sense that microbes would need some help but do PH buffers not in turn kill a lot of microbes? I still have tons to learn and I enjoy it so info is welcome. I’ll get a couple leaf pics up here shortly
 

waktoo

Well-Known Member
Eggshells. Dry them, bake for 20 min @200°f, crush them, using a non-nonstick pot boil about a half cup of shells in 2 cups of distilled water till half if the water remains, stirring frequently. Let it cool and give her the water. Hell, you can dump the entire contents, shells and all. The water will give her an immediate CA boost and the shells will amend the soil with CA as they degrade further. I pulled 388ppm of CA to add to my hydro girls. If it is a mag issue I've read Epsom salts have mag, I just don't know how much to give them safely.
Do you have a citation/reference for this procedure? The chemistry doesn't add up. Boiling water doesn't solubilize calcium carbonate.

Also, how were you able to determine the calcium concentration (388 ppm) of your final solution?
 

TreeFarmerCharlie

Well-Known Member
Your lime will probably do the trick over a few days if it's powder. The web says it takes 2 years to work but plants says otherwise lol
I honestly don't understand why people say lime takes so long to act in soil. When I had a reef tank a common way to supplement low doses of calcium was to build a "kalkwasser" chamber which was nothing but a water filter filled with lime that the tank water slowly flowed through. When we needed much more calcium we moved up to calcium reactors which are chambers filled with crushed oyster shells (and other hard calcium deposits) which have water flow through them with CO2 injected to help make the calcium water soluble.
 

Harry Bonanza

Well-Known Member
So far it’s a small percentage and these are 2 slower growing runty types from a sexing project I decided to put in the flower tent
0C23DB82-D5AC-4F81-8AD5-B9FD9679EE26.jpeg
 

getogrow

Well-Known Member
Thats just a simple lack of veg food. Give her some instant food an watch her grow! I agree with the one that said the lime will work on its own in a few days. it has plenty of Ca in it. But i dont thinnk thats your only prob. i think you need a well balenced diet of veg food. or anything high in N. Thats VERY common in the organic world. Something in your soil didnt break down as fast as needed to feed so thats where were at now.
 

Polyuro

Well-Known Member
Agree with getogrow. That looks like more than cal/mag. Manganese, zinc, etc...? looks like micronutrients are needed unless your roots are locked out And it’s already in there. Is it the same soil as other healthy plants?
 
Top