Mixing my own Earthbox Growing Media

My old Earthboxes perform well, filled with Miracle Grow Potting Mix and topped off with a bit of compost. But I got even better results those first couple of years when I purchased complete kits that included Earthbox brand growing media. Unfortunately, I dumped the Earthbox brand media into my raised garden beds, unaware of how hard it would be to find the recommended replacement media.

Earthbox Suggested Growing Media

  • 70-90% Sphagnum Peat Moss
  • with Perlite or Vermiculite
  • Light and fluffy when dry, spongy when wet

Earthbox Brand Growing Media

  • 80% Canadian Sphagnum Peat Moss
  • 10% Perlite
  • 10% Vermiculite

Earthbox Phone Support: When I called Earthbox phone support and told them that I was having trouble finding the suggested media in my area and would like to try mixing my own, they suggested I add 1 lb Vermiculite or 1 lb Perlite per cubic foot of peat moss. I actually just wanted to confirm that the published measurements were by volume. But seeing how many cubic ft the bag of peat moss says then measuring out that many pounds of perlite or vermiculite sounds easy!

Young Swiss Chard Plant

Unfair Mom’s Growing Media Recipe #1

With a little research, I decided to copy Earthbox in using both Perlite and Vermiculite. This recipe should make a little more than the 4 cubic ft of growing media that I need to fill my 2 new Earthboxes:

  • 3.8 cu ft bale of Canadian Sphagnum Peat Moss
  • 2 lb Perlite (about 1/3 cu ft)
  • 2 lb Vermiculite (about 1/3 cu ft)

This recipe ends up being about 85% Peat Moss, 7.5% Perlite, 7.5% Vermiculite.

Unfair Mom’s Growing Media Recipe #2

  • 3.8 cu ft bale of Canadian Sphagnum Pat Moss
  • 2.5 lb Perlite (about 0.4175 cu ft)
  • 2.5 lb Vermiculite (about 0.4175 cu ft)

This recipe ends up being about 82% Peat Moss, 9% Perlite, 9% Vermiculite

Compromise Recipe #3

  • 3.8 cu ft Canadian Sphagnum Peat Moss
  • 2.25 lb Perlite (about .37575 cu ft)
  • 2.25 lb Vermiculite (about .37575 cu ft)

This recipe ends up being about 83.5% Peat Moss, 8.25% Perlite, 8.25% Vermiculite

Let me know if you use one of these! This post is still a work in progress – I am publishing my notes so I can double-check the price of perlite and vermiculite and decide how much to use. What was suggested over the phone or what is closer to what Earthbox published on their site.

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