Gypsum in Coco

[MillerJohn]

High All!!
Greetings, been patronizing this forum for months, but this will be my first post in this forum....

I've had problem with rising ph (in 5.8 out 7.5) and lockout on my coco when I still amending my coco with dolomite lime.... Got rid of it with shitload of flush....

Now I have no problem with lockout or any PH problem (in 5.5 out 6.1) but now I am battling calcium deficiency problem.

I do not have possible source (not even mail order) for calmag+ and even if I can make my own calmag, I don't feel comfortable adding nitrate to my flowering plants as I had an experience with real bad clawing on my previous grow.

What do you guys think about gypsum? Does anyone have any experience with amending coco with gypsum?? Any Ph issue?? Dosage/ratio??

Here is my setup:

50-50 coco/perlite on 2.5 gal pot
400W Hps
Temp 75-82F
RH 45-60%
Maxibloom KISS method + 1tsp epsom/5gal, Tap water @90ppm (hanna), ph to 5.5, DTW with 40% runoff everyday once a day..


Is there any other safe and ph neutral calcium source that are readily available from normal chemical store??

TIA guys!!

 

[Granger2]

John, I can't help you much, but I'll give you the little info I have about gypsum. It is Calcium sulfate. Has a neutral pH. Commonly used to help drainage/aeration in clay soils. I can't tell you how much Ca it surrenders nor how quickly.

That's why I have almost entirely stopped using dry amendments in coco. I don't know what's being released when. Why so much perlite? I use about 20%, but 50 seems unnecessary. Buena suerte.

 

[MillerJohn]

Thanks for the answer dude..Yes, I did a search on google and had so many references stating that gypsum is ph neutral... However after my horror story with dolomite I became a bit paranoid about adding stuff to my coco...

I heard some people use gypsum with success, but I couldn't find any thread with comprehensive instruction or method on this... It kinda make sense thought, pure calcium with neutral ph, should be perfect...

I think the calcium content should be become available to the roots really soon, I have tested adding some gypsum to tap water and the ppm would climb up rapidly, I think that means the calcium is readily available in soluble form.. The PH would rise about 2 points, but that is with lots of heaping spoonful on a pint of tap water... If I do the same experiment with dolomite, the PH would rise 5-6 points...

My mistake on too much perlite... I made lots of mistake on coco including scary dolomite problem because I was following method and suggestion of some so called 'coco evangelist' from another forum.... The perlite does not give any problem to the plants, but it make everything dries up real fast and giving my lazy ass a problem...

 

[MillerJohn]

It would be great also if someone could suggest calcium addition other than calmag that is easily available from any general chemical supplier.... I am using epsom for my magnesium and my plants does not show mag def...

 

[medical marvel]

Molasses has calcium..i could never get it to work on its own.
Low EC water.

If you go easy on the Calmag you can find a balance. I stop Calmag in the last 3 to 4 weeks of flower. You shouldn't have "clawing" that is also a sign of general over ferts, so the Clamag probably pushed your EC over the edge. Try 1/2 tsp per gallon 2.5 ml ) and add a little extra epsom salts, I was able to lower the Calmag and use epsom, as the plants were getting enough Calcium. Easy does in so you don't create other lockout issues.

good luck !

 

[jackiee]

hi have you tried buying bottles of calcium from your grow shop,i bought a bottle of calcium and a bottle of magnesium as sometimes plants want one without the other which you cant do with calmag. i bought mine from growell hydroponics. hope this helps and stay lucky

 

[MillerJohn]

Thanks for the suggestions....

I just don't feel comfortable adding nitrate to blooming plants... Therefore normal calmag is out of the window.... That and the fact that I do not have access to ready made calmag, I have to make my own calmag from calcium nitrate and epsom...

Due to work, I am living in SE Asia now, so getting hydrophonic specific stuff is a real PITA....However, serious reef keeping is huge here... Do you think I can get away with liquid calcium for coral reef tank?? There is nothing salty about it AFAIK. Mix it with my daily nutrient schedule eh??

My main question hasn't been answered tho... Is gypsum safe and effective??

I have no problem with mg def, just ca def...

 

[simos]

My main question hasn't been answered tho... Is gypsum safe and effective??

Gypsum is totally safe, and it conveniently helps block plants' uptake of salts. It's definitely a good source of calcium over the long run, but won't give you the adjustability of a liquid additive.

You might look into powdered/pulverized oyster shell lime as well. I find that it's a great a faster-releasing complement to gypsum, but my mix is coco based soilless, and I have no idea how many amendments you're willing to add.

Another thing to consider would be Azomite - an awesome source of trace minerals. Again, powdered might be better than granular if you have the option.

Good luck

 

[MillerJohn]

Thank you very much. I decided to give it a try... 4 tblspoon in 2 gal of coco. Went straight 4 days DTW with barely any runoff. No lockout on all flowering plants, except one vegging plant now showing mag def instead of cal def.