MustangStudFarm
Well-Known Member
I've been having my soil(indoor potting soil) tested for about 3yrs now and I noticed that common trend that I have is Mn is always low. I always thought that I could just amend my soil and be done with it, but I would usually start to see Mn def around mid-flower and I couldn't believe it and thought that it was something else. However, I came across this article and it changed my mind about how I approach the issue. This statement alone cleared up a lot of questions, but the whole article is worthy of reading. Keep in mind, what they mean about heavier soil is high organic soil such as indoor potting soil.
In heavier soil, the problem usually involves getting plants to take up manganese from the soil before it becomes tied up and unavailable. “In such soils, broadcasting, in my experience, is pretty inefficient,” Ferrie says. “Doubling the amount of manganese in the soil won’t help. If you do choose to broadcast, apply the manganese as close to uptake by the plants as possible because anything not taken up will quickly become fixed and unavailable.”
They go on to say that foliar feeding is the best way to deliver Mn. However, I listened to podcast with Dr. Steve Solomon and he has written books about soil mineralization and he said "You don't feed a man one huge meal once a month, but you spread it out and give smaller amounts but more often" he was talking about the approach to fixing soil deficiencies. I was guilty of testing my soil and only adding Mn 1x for the entire grow cycle and calling it good. I also found out the hard way that you can easily add to much Mn sulfate and cause Mn toxicity too, so I stopped using Mn sulfate and I moved on to Big 6 but I think that TM-7 would be helpful to some people instead. Dr. Steve Solomon is really helpful in understanding this stuff and I'll leave the link to to it. https://www.kisorganics.com/pages/6-cannabis-cultivation-and-science-podcast
If you took the time to read my post, you should look at these links because they were very helpful in what I felt like was my "Darkest Hour" of growing. I was hitting my ceiling and I was getting frustrated because I couldn't find the answers that I was looking for. On the podcast Dr. Steve Solomon talks about cannabis being a Mn sensitive pant and that rock dust doesn't have enough to make a difference. He basically said that the only way to get a source of Mn is from Mn sulfate. He said that it would take an entire dump truck of 2tons to get a cup of zinc or manganese. Anyways, these soil tests are what my tests typically look like:
In heavier soil, the problem usually involves getting plants to take up manganese from the soil before it becomes tied up and unavailable. “In such soils, broadcasting, in my experience, is pretty inefficient,” Ferrie says. “Doubling the amount of manganese in the soil won’t help. If you do choose to broadcast, apply the manganese as close to uptake by the plants as possible because anything not taken up will quickly become fixed and unavailable.”
They go on to say that foliar feeding is the best way to deliver Mn. However, I listened to podcast with Dr. Steve Solomon and he has written books about soil mineralization and he said "You don't feed a man one huge meal once a month, but you spread it out and give smaller amounts but more often" he was talking about the approach to fixing soil deficiencies. I was guilty of testing my soil and only adding Mn 1x for the entire grow cycle and calling it good. I also found out the hard way that you can easily add to much Mn sulfate and cause Mn toxicity too, so I stopped using Mn sulfate and I moved on to Big 6 but I think that TM-7 would be helpful to some people instead. Dr. Steve Solomon is really helpful in understanding this stuff and I'll leave the link to to it. https://www.kisorganics.com/pages/6-cannabis-cultivation-and-science-podcast
If you took the time to read my post, you should look at these links because they were very helpful in what I felt like was my "Darkest Hour" of growing. I was hitting my ceiling and I was getting frustrated because I couldn't find the answers that I was looking for. On the podcast Dr. Steve Solomon talks about cannabis being a Mn sensitive pant and that rock dust doesn't have enough to make a difference. He basically said that the only way to get a source of Mn is from Mn sulfate. He said that it would take an entire dump truck of 2tons to get a cup of zinc or manganese. Anyways, these soil tests are what my tests typically look like:
