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Using Diatomaceous Earth as a Silica Suppliment

by | Nov 8, 2019 | Grower Questions | 8 comments

I got some diatomaceous earth (Gaia Green Brand) to take care of some fungus gnats and it did the trick.

I soon learned that DE is also a decent source of silica, and I figure since I already have this stuff lying around and it has other benefits, I might as well use it. My problem is when trying to research its use in this way, I come up with almost nothing. Tons of info on using DE to control pests but not much for using it as a source of silica.

I’m currently on week 4 of flower and I was thinking of watering some DE into my soil at a ratio of 1/3 cup per 4 liters (1 gallon) of water. My questions are: will this be effective? How long will it take for the silica to become plant available?

Other details:

I’m growing in Pro Mix HP, amended with Bokashi Gro and using Medi One 4-3-3 as my nutrients.

Thanks!

8 Comments

  1. Coach Steve
    Coach Steve on November 9, 2019 at 8:58 am

    There’s very little silica in DE, not going to be beneficial. I’ve used it before for gnats and after I watered over it I hated what it did to my soil. I don’t remember well enough to describe it other than ewww!

    • rusty_shackleford
      rusty_shackleford on November 9, 2019 at 5:59 pm

      According to wikipedia, DE is 80-90% silica.

      Ya it gets mucky when you water over it after top dressing. That’s why I plant to mix it with my water and water it in.

      • Coach Steve
        Coach Steve on November 10, 2019 at 12:43 am

        Weird, I researched your exact question a few years ago and concluded that it wasn’t a good way to deliver silica. I can’t find any bookmarks on it. My bad though if I gave wrong info, I may have been mislead by its crystalline silica content…I’ll have to figure out wtf I got my info from, but sorry again.

        • rusty_shackleford
          rusty_shackleford on November 10, 2019 at 12:31 pm

          No worries man. I know there are probably better ways to give silica, but I’m mostly asking because I already have this DE lying around. I did see the post you linked below, but it doesn’t really say how long it takes to become plant available.

          I don’t want to bother adding it now if it’s going to take 30 days for my plants to take it in, and then I’m almost done flowering anyways, so not useful.

          It’s hard to find info on this specific use for DE. Most info is about pest management. I’ve only found the previous post you linked and a few other forum posts but it’s not very comprehensive.

          I’ll keep looking into it myself and post anything if I find it. But I was hoping someone smarter than me already knew the answer.

          Thanks for your efforts in trying to answer.

          • Coach Steve
            Coach Steve on November 10, 2019 at 12:57 pm

            I looked through my bookmarks trying to find what the hell I saw lol. I still don’t know why I thought there was little silica in DE, wasn’t using my head for that one. I did find some stuff I saved about it working as a top dress, but to mix with water and become immediately plant available I believe you’ll need to mix with water having pH of 9. There’s a lot I don’t care to understand about that lol.
            Anyway no problem man, sorry I couldn’t be more help.

    • rusty_shackleford
      rusty_shackleford on November 12, 2019 at 9:31 pm

      Thank you for the quality links., especially the journal article. Looks like it is a decent source of silica. Still wondering how long it takes to become plant available. I will have to read through the journal article when I have more time, and see if I find my answer.

      Seems like a decent, affordable source of silica and effective pest prevention. Still surprised it isn’t talked about more as a silica supplement.

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