Author Topic: Growing medium question  (Read 212 times)

tankertoad

  • Newbie
  • *
  • Posts: 16
Growing medium question
« on: April 08, 2021, 10:34:57 pm »
I am replanting my Earthboxes with last year's Earthbox growing medium and need to add a bit of growing medium to it.  It is very difficult to find an appropriate substitute in my area so I want to mix my own, since I think I can easily find the ingredients.  The Earthbox website says the growing medium should be "Sphagnum peat-based (70%-95%) that contains perlite or vermiculite."  Does that mean it would be, for example, 70% sphagnum (by volume) and 30% perlite (by volume), or is there something else that is in the Earthbox version besides those two things?  Thanks

gardendoc

  • Global Moderator
  • Full Member
  • *****
  • Posts: 224
    • Changing the Garden Paradigm
Re: Growing medium question
« Reply #1 on: April 12, 2021, 09:21:07 am »
Don't mix your own, it will alter the water holding capacity. Any commercial mix engineered for containers will work. MG (yellow/green) bag, MG Moisture Control (blue/black) bag are fine. Independent garden centers usually carry commercial professional mixes, like Jolly Gardener, Promix, Sunshine, etc
Why Google, when you have me?

tankertoad

  • Newbie
  • *
  • Posts: 16
Re: Growing medium question
« Reply #2 on: April 18, 2021, 03:41:39 pm »
I appreciate your response, but since I didn't get one quite soon enough, I did mix my own using appropriate (according to some research I did here on the forum) amounts of sphagnum peat moss, perlite, and vermiculite.  I could find the mix you recommend, but the ingredients included mycorrhizae and "ground limestone", neither of which are specifically mentioned by Earthbox for Earthbox usage.  I know what mycorrhizae is/are (wasn't sure if it was Earthbox compatible), and "ground limestone" didn't sound specific enough (to me) to necessarily be an appropriate substitute for dolomite, which is apparently a specific calcium magnesium carbonate found in varying concentrations depending on the "ground limestone" containing it.  Just "ground limestone" seemed incomplete, so I just added the Earthbox re-planting kit dolomite as usual when re-planting my boxes.  When I re-plant, I do empty the boxes, clean out the old roots at the bottoms, and then re-use the medium per the instructions.

I've had very good luck with Earthboxes, but didn't want to buy another bag or two of the planting medium on-line and then have it sitting around for a year if I could locally find a suitable medium for replacement of the relatively small amount I needed.  Next year, I'll consider use of the Pro-Mix you recommend, or just get a bag of medium from Earthbox If I need to add growing medium.  Thanks.

gardendoc

  • Global Moderator
  • Full Member
  • *****
  • Posts: 224
    • Changing the Garden Paradigm
Re: Growing medium question
« Reply #3 on: April 19, 2021, 09:47:32 am »
You did great. Happy growing this year
Why Google, when you have me?