Quick question regarding dolomite/OSF

Discussion in 'Growing Organic Marijuana' started by Ancient3328, Aug 17, 2018.

  1. Hey guys, so I believe I am having a PH issue in my living soil mix. I mixed following the no till revisited thread but did add alfalfa and biolive as well. The reason for me thinking it is a PH issue is due to the fact that my plants are showing signs of something that looks like a mixture of a manganese deficiency and a potassium deficiency (yellowing outsides, green veins, crispy tips with dark spots). The strange part is it is just appearing on random leaves and it is not necessarily on new growth or old growth, usually it shows up in the middle area of the plant. I do have some nice colored leaves but different plants have different shades of green. They are definitely still growing and surviving but the water amount they are using is pretty small for 10 gallon pots. I am giving them roughly 6 cups every 5 days and these are over two feet tall at this point so I know something is up.

    My question is, rather than get stuck in trying to fight a deficiency that probably does not actually exist, I was thinking of top dressing some dolomite or OSF for a quick fix. I did put both of these into my initial mix but feel like I may have gone light on them and that is why I am seeing these issues. I would post pictures but my camera is on the fry currently so I hope you guys can still help in the mean time until I resolve the issue with it. Thank you!
     
  2. FWIW, I stopped using Ag lime (same as OSF but different source), in container mixes because of Mg deficiencys and only use dolomite. I've also increased the application to 1 1/2cups/cf, since my mix tended to the acidic.

    It's kinda hard to over apply lime, but you can sure under apply it, as you've noticed. A top dress is going to be slow, but will work in time. If you can scratch in into the surface, even better. Since you have some lime in there 1Tbl/gallon of mix in the container should do. The normal amount is 2Tbl/gallon. So, play it by ear as how much you added in the first place.

    It takes a bit longer for the Mg in the dolo to release compared to the Ca component, so a bit of epsom salts might be in order. I usually have to add some with fresh mixes. Once the dolo starts to release no more is necessary and I usually need to do it once. 1tsp/gallon of water as a soil drench works fine.

    Not adding enough lime creates problems in the long term as the peat and amendments break down and get more acidic. Now at least, you've seen for yourself the importance of using enough from the start.

    Good luck!

    Wet
     
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  3. It would be helpful to have your exact soil mix and a pic or two of your plants.
    RD
     
  4. @wetdog Yeah, I think I am over the whole OSF craze. I always had great luck with dolomite and for some reason switched over which I will be switching back from moving forward. I will also up the amount per CF as you recommended as it seems better to have more than too little.

    I think I will take your recommendation and scratch it into the surface and use epsom salts in the mean time to hold it over.
     
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