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Can I foliar feed cal/mag?

Hey DGC!
So I am a medical cannabis patient and grow my own medicine. I have done dwc for a couple years. But have recently switched over to dual root zone aquaponics and even pulled my first successful harvest of some Critical Kush. I am wondering if I can foliar feed cal/mag so that I don’the rise the ph of my fish water, it’s right where I want it right now. Right now I am feeding Recharge, LABS serum and cal/mag to the soil portion. But I’d like to be able to foliar feed. And what do you guys think of adding silica to the mix, Can that be foliar fed?  Thanks!


11 responses to “Can I foliar feed cal/mag?”

  1. E. Elmo Phudpucker Avatar
    E. Elmo Phudpucker

    Hey Indi – You bet you can! Foliar sprays are a great way to tackle nutrient deficiencies. Just remember a couple basic “Do’s & Don’ts”

    1. Spray only when your lights are out. Spraying with lights on can create a serious issues. A) The liquid will act as a lens, magnifying the heat from the lights and burning the leaf. B) The plant can choke. Usually, when a plant gets too hot, its stomata open to release heat, gas, and water to cool down. However, it will not be able to breathe or self-regulate if the leaf is covered in a liquid that is causing its surface to burn.

    2. Spraying to much can create a humidity issue which can bring a wide variety of nasties like powdery mildew, fungus gnats, thrips………

    3. Read and FOLLOW the label!!!! Don’t be a “More On” Farmer. More is not better. I recommend 3/4 strength spray just to make sure that you don’t use a mix that could be too strong for your plant.

    4. Use a wetting agent. I like Optic Foliar Transport. The science behind it really works well.

    1. callumsupreme Avatar

      Can you give me a recipe to make this foliage spray

      1. jmystro Avatar

        An effective foliar has a way to get minerals like calcium in the leaf fast. Fulvic acid, minerals and a surfactant make a great combination. Fulvic acid like ruby Fulvic will be able to carry calcium, magnesium and other metals into the leaf quick with the aid of a surfactant like Optic Foliar Transport. Less than a teaspoon (5 ml) per gallon of each is plenty. Silica is optional and can cause more harm than good so I caution using it.

  2. Indica_Dogo Avatar

    Thank you for the great info Elmo!

  3. OG LABS Avatar

    To Elmo phudpucker, wouldn’t spraying during lights off invite mold or pm issues? Wouldn’t be better during lights on and just dim them down a bit to take the edge off?

    1. jmystro Avatar

      Water beads on leaf surfaces without a surfactant and will magnify light like a lens causing burn. Transport will prevent this but dimming the lights is the best way to go and also have fans off. Dehumidification is still a serious concern, so dehumidifiers need to maintain the proper RH day or night. Dimming the lights will help prevent water evaporating quick.

  4. E. Elmo Phudpucker Avatar
    E. Elmo Phudpucker

    Fantastic follow question OG! I should have added spraying should be done roughly 1 1/2 to 2 hours before your lights come on. I am an outdoor grower and have fund success spraying during morning twilight. This gives your plant ample time to absorb the foliar feeding before the chances of getting leaf burn. I also should have added, I don’t recommend spraying flowers, with anything, after week 2 or 3.

    Regarding PM issues. PM is thwarted through proper humidity control, which we all generally know, but just as important, conquering pm begins when you build your soil. Maxing calcium uptake allows for your plants to build calcium pectate between cell walls. When your plant has ample amounts of calcium it will build Calcium pectate between cell walls rather than holding water there. This greatly lessens the chances of pm getting feeder tubes established.

    I also strongly suggest applying lactobacillus serum as a foliar . Lacto serum will battle plant pathogens, bud rot and mold.

    For your future grows, I would add oyster shell flower OR baked and powdered egg shells to the soil portion in Indica’s grow if you already haven’t.

  5. Indica_Dogo Avatar

    Thanks again Elmo!
    I have recently discovered LABS and Ferments! I also followed a couple YouTube videos on how to diy calcium with eggshells.

    One said bake em and let em sit in water for a month to dissolve. The other said bake em and add vinegar and it’ll breakdown the shells. And we’ll neither has dissolved the shells yet so I haven’t tried it.

    But I need to get my ass in gear and try to use em and try making LABS and Ferments!

  6. MeefChief Avatar

    In regard to the initial comment, you can spray with lights on using Optic Foliar Transport.

  7. NewbieDoobie


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