Making Potting Soil

Posted on Jun 5 2009 - 1:00am by Mike Lieberman

In a previous post, I explained the basic differences between coconut coir and peat moss based potting soils. Now I am going to show you how to make your own potting soil using a peat moss base.

Here’s what you need to make your own organic potting soil:

  • Sphagnum peat moss – holds water and air; provides little nutriton
  • Vermiculite – provides minerals (potassium, calcium and magnesium)
  • Garden lime – provides minerals (calcium) and balances acidity of peat moss
  • Compost – provides the lion share of the nutrition to the plants
  • Large bin to mix it all in. Watch the video and you’ll know why you’ll need to use a large bin.
  • To mix it:

  • Add the mixture at a close 1:1:1 ratio of the peat moss: vermiculite: garden lime. You definitely want peat moss to be the dominant ingredient. Mix well.
  • Now that you have the peat moss mixture, add an equal part of compost. Mix well.
  • Add some water to dampen the mixture. Don’t want to saturate it. Mix well.
    • http://www.meghantelpnerblog.com/ Meghan

      I love that you do your gardening outside- but mix up potting soil inside… and that you are mixing it yourself is taking it to a whole new level of home grown. I love it Mike!

    • Mike Lieberman

      Thanks Meghan. I did little reading before starting all of this and in the little reading that I did, there was conflicting info. So I figured do both…screw it. Let me learn on my own. I quickly learned not to mix potting soil in a 4 gallon bucket that's painted green and pink stripes…bad move.

    • Del

      Mike, When wetting your mixture, all a little Ivory Soap to your water. (I just swish a bar of soap in the water bucket or a couple of drops of liquid Ivory). The soap is a “wetting” agent that will make the soil soak up the water quickly. Looks good!!!

    • John L

      Great blog post! I love learning about this online as gardening/landscaping are not only hobbies of mine but I actually do a little bit of work like that during the summer months as a second job. I appreciate your content in your blog and wish that you would keep up the good work :)

    • Mike Lieberman

      Thanks for the tip. I might use Dr. Bronner's liquid soap instead. Would want to stay away from the chemicals in the Ivory Soap.

    • Mike Lieberman

      Thanks for the tip. I might use Dr. Bronner's liquid soap instead. Would want to stay away from the chemicals in the Ivory Soap.

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    • http://www.facebook.com/profile.php?id=96300123 Jamie Banister

      This is exactly the article that I’ve been hoping to find. I’m just getting started with gardening. Will I be able to find all these ingredients for the soil at my local nursery (or maybe at a bigger place like Home Depot)? I can’t make my own compost in the place where I live.

    • http://www.UrbanOrganicGardener.com Mike Lieberman

      You should be able to find them at your local nursery. Personally I’d stay away from Home Depot as they mostly sell Miracle-Gro and Scott’s products.

    • Powerser

      Hey Mike, any idea how much these materials will cost me?

    • http://www.UrbanOrganicGardener.com Mike Lieberman

      Depends on where you get them. 

    • Limey

      Am I reading 1:1:1 peat:vermiculite:lime?
      Same volume lime, as peat moss? That is an incredible amount of lime!!! Burn your hands off, let alone the plants. I think about 1 cup lime per cubic feet of final soil mix is plenty, is that a mistake or is there some reasoning? I don’t want anyone to make the mistake if it’s avoidable :)