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rt_peasant

5-1-1 Mix with MG Organic Choice?

rt_peasant
10 years ago

I recently bought a bag of Miracle Gro Organic Choice for potting up some tomato seedlings. I must say, I'm very dissapointed with this product. It appears to be a mix of shredded sapwood, peat, and DPW fertilizer. Some of the chunks of wood are bigger than my thumb. Many pieces are over 3" long. Not at all a consistent particle size. I tried bottom watering the pots in 1" of water for an hour, and there was no wetting at all above the water line. I finally dunked the pots to get them wet, which turned everything into a soggy mess. A week later, after setting the pots on a sunny windowsill with a fan blowing on them, the soil is still sopping wet. My seedlings have shown minimal growth since I potted them up, they have pale colored leaves, and many of the leaves are diseased after getting the mix on them. By contrast, the seedlings that I potted up using soilless seed starter are thriving!

Oh well, live and learn. Enough ranting about MGOC. I now have a bag of the stuff that I'd like to use up, and I was thinking about converting it into a 5-1-1 mix, for use in a container for tomatoes. I was thinking that I would run it through a 1/2" screen to get out the large chunks, then treat the screened product like mostly peat and CRF in a 5-1-1 mix. It's not pure peat at that point, since there is still some of the smaller wood pieces, so I might add a touch more to compensate. Maybe 5-1.25-1 or so.

Any thoughts on this approach?

FWIW, this is my proposed mix. All of the materials came from my local HD.
5 Permagreen Deco Bark Small Nuggets (1/2" screened)
1.25 Miracle Gro Organic Choice (1/2" screened)
1 Perlite
1 tbsp per gal Espoma garden lime
(no CRF, since there's some in the MGOC)

Comments (11)

  • tapla (mid-Michigan, USDA z5b-6a)
    10 years ago

    Is your bark actually nuggets? It should look something like this:

    {{gwi:20506}}
    {{gwi:20507}}

    Slightly finer would actually be a little better.

    End product:

    {{gwi:20508}}

    Al

  • rt_peasant
    Original Author
    10 years ago

    This was the closest thing I could find at my local HD to your description of bark fines.
    {{gwi:20509}}

    I have a 1/2" screen that I was going to run these "nuggets" through. A penny is 3/4", so a lot of this will get screened out, I think.
    {{gwi:20510}}
    Does this look like it would work?

    Mark

  • tapla (mid-Michigan, USDA z5b-6a)
    10 years ago

    You're going to need to add so much peat to it to get the water retention you'll want, that aeration/drainage will essentially be the same as if you were using peat only. The peat will simply fill in between the large particles of PB. In a perfect world, the largest pieces would be about 1/3 - 1/4 that size, and the smallest pieces dust. 0-3/8 is ideal, with the bulk of the bark product in the 1/16-1/4" size range. {{gwi:20511}}

    Al

  • dsb22
    10 years ago

    Al,
    If the pine fines were the size you recommend, would it be possible to use the OP's proposed recipe?

    5 0-3/8" sized bark (majority 1/16-1/4" size)
    1.25 Miracle Gro Organic Choice (1/2" screened)
    1 Perlite
    1 tbsp per gal Espoma garden lime

    I have some of the Organic Choice too (although I don't think mine has the bark chunk and sapwood issues) and am interested in finding a use for it.

    Thanks,
    Deanna

  • tapla (mid-Michigan, USDA z5b-6a)
    10 years ago

    Yes it would. That's very close to the 5:1:1 mix I use and would be a very good medium - assuming the difficulty the OP was having with the MGOC was a structural issue (too water-retentive), rather than a chemical (toxicity) one.

    Al

  • dsb22
    10 years ago

    Terrific, thank you!

    Deanna

  • rt_peasant
    Original Author
    10 years ago

    Ok, thanks for the guidance on the size of the bark fines. The handful I showed was from the upper part of the bag. The lower part of the bag had much finer particles. I may be able to get enough small particles from this one bag to fill my container. I might need a finer screen, though. Or I may try chopping them up with my lawnmower.

  • rt_peasant
    Original Author
    10 years ago

    I made up my modified 5-1-1 mix this weekend with the Miracle Gro Organic Choice. Here are some pics.

    Pine bark "small" nuggets before screening:
    {{gwi:20510}}

    Pine bark nuggets after screening:
    {{gwi:20512}}

    The big chunks from the Miracle Gro Organic Choice that were removed by the 1/2" screen:
    {{gwi:20514}}

    The MGOC post-screening. There still is quite a bit of wood in it.
    {{gwi:20515}}

    I'm guessing that MGOC straight out of the bag is roughly half wood, half peat. Screening out the big chunks still left the mix with a lot of splintered/shredded wood particles. I increased the amount of screened MGOC to compensate for the fact that it has less peat than I originally thought.

    Here is the ratio that I wound up with (it's roughly 5-1-1):

    5 parts 1/2" screened pine bark
    2 parts 1/2" screened Miracle Gro Organic Choice
    1.25 parts perlite
    1 Tbsp per gal Espoma garden lime

    In hindsight, I think a simpler, almost equivalent ratio might have been 4:2:1.

    Here is the final mix:
    {{gwi:20516}}

  • rt_peasant
    Original Author
    10 years ago

    One more thing to add about this mix. I buried my hand in the watered potting mix a day later, and was surprised at how warm it was. Not quite hot, but definitely a steamy, warm temperature, like a compost pile at work. I don't know if that is normal for fresh 5-1-1 mix, or if it is because of the ingredients that I used?

    This might actually be a benefit to me. I'm using this mix to grow tomatoes, and I think my tomato plant will be happy to have warm roots!

  • dsb22
    10 years ago

    Wow, that's a lot of bark in the pre-screened MGOC. I'm personally done with buying MG, I recently bought ProMixBX for my Earthboxes and it is lovely. (I thought using it in bale form was going to be a hassle but I've found it to be very easy, other than needing help carrying it.)

    Anyway, if the potting mix was in the sun, I'd think that could easily make it feel warm and steamy. Of course if there's too much composting going on too quickly, it will tie up nitrogen in the soil. Hopefully someone can give you feedback on the look of your final mix.

  • rt_peasant
    Original Author
    10 years ago

    Anyway, if the potting mix was in the sun, I'd think that could easily make it feel warm and steamy. Of course if there's too much composting going on too quickly, it will tie up nitrogen in the soil.

    I didn't mention this, bit it was the next morning that I felt the warm mix, and the container was in the shade. The air temperature was in the 50s, which may have accentuated my perception that the mix was warm. I share your concern about composting and nitrogen..