What is in Miracle Gro Potting Mix

When I think of Miracle-Gro, fertilizer comes to my mind’s eye. This immediately makes me think that Miracle-Gro potting mix also contains a chemical-based fertilizer by association, I guess. In this article, I will list and explain what is in Miracle-Gro Potting Mix.

I will also give my recommendations for using it as a potting mix for growing microgreens. These opinions are mine, but I will give reasons and show you the results of my test that my conclusions are drawn from so you can judge for yourself if you want to use it on plants you grow for food.

close up of the texture of miracle gro potting mix

Part of a Series on Potting Mix (maybe all grow media)

This article is part of a series on the ingredients of potting soil. There will be links to all of the soils in this series as they are published so you can make the best-educated decision on what to use to grow microgreens.

What is in Miracle Gro Potting Mix?

All indoor potting soils should be called “Mixes” because they are not soils. So, if I slip up and write or say soil, it’s because I use it interchangeably from years of not understanding the difference. I don’t want to confuse you when I mix the two.

Listing of the Ingredients of Miracle Gro Potting Mix

The ingredients listed below are directly from the label or the Scott’s website. Because there are so many different Miracle Gro mixes and blends, I want to clarify the ingredients listed are from the label on the yellow and green bag as shown in the cover image at the date the article was published.

Miracle Gro Potting Mix Contains:

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  • Sphagnum peat moss
  • Processed forest products
  • In Georgia, the mixture is 45 – 55% composted forest products.
  • In New Hampshire, forest products are replaced with Processed softwood bark.
  • There is no mention of what the percentages are elsewhere. 
  • Perlite
  • compost 
  • Fertilizer (below)
  • Yucca
  • Processed Forest products
  • Peat moss
  • Coir
  • and/or compost?
  • Sphagnum peat moss
  • Perlite
  • Fertilizer – see components below
  • Wetting agent
  • Polymer-coated ammonium nitrate (fertilizer component)
  • Ammonium phosphate (fertilizer component)
  • Potassium sulfate (fertilizer component)
  • Calcium phosphate (fertilizer component)

If an ingredient listed above is orange, you can click that link to learn more about it if you are interested or curious.

Ingredients Will Vary Depending on the State

If you buy Miracle-Gro Potting Mix in any of the states below, the ingredients will vary by the listed.


The order of the ingredients is changed, meaning that the higher on the list contains more either by weight or volume. I know for foods, it is by weight, but for products sold by volume, it might be most volume first.

Also, notice that coir and compost are not listed.

Texas & Idaho

In these states, again coir is not listed, and compost is added in small quantities with more sphagnum peat than fine peat.

New Hampshire

I guess New Hampshire wants Scott’s to use the state’s waste pine bark and unusable log products in the potting mix. I find it odd that the bark and wood products are labeled as composted. But I guess the forest products aren’t either. But that has to be a given. You will also see no coir, compost, or fine peat in Miracle-Gro Potting Mix sold in New Hampshire.


Georgia is getting specific on how much forest products need to be used in the mix. Again, no coir is added to mixes sold in Georgia.

Recommendations Based on 1st Ingredient List

The mix I bought was the first listed with coir, maybe compost, more fine peat than sphagnum peat moss, and regular mixed forest products rather than softwood or bark forest products. The recommendations below, good and bad, are from using that mix, not the ones sold in the listed states.

I’d be curious if the label is accurate and the components vary by state. If you think about it, how do the large box stores buy specific potting mix blends for their stores? Maybe it depends on where the product is purchased, even wholesale.

I know Home Depot headquarters are in Atlanta, Georgia. I purchased from HD in New York but didn’t have the Georgia mix. But that doesn’t mean that even HD orders from their headquarters.

I’d be curious if you are from one of the listed states. Let me know what the label says. You don’t have to buy it; send me a photo attachment to to**@ho*************.com. I’d like to know.

Anyway, My Thoughts

I can’t tell you right now; I’m still running tests. But when I do have the results, I’ll publish them at a future date near the bottom of the article.

What I do know at this time I will post below.

The Miracle-Gro Potting Mix I purchased was reasonably fine-grained. It has some larger pieces of forest products. So it was more coarse than my Home Microgreens Mix. It was not as coarse as the mix I used to use, the Fox Farms Coco Loco Mix.

It did wet pretty well, but not as fast as the HM Mix, which contains more coconut coir. You will see this in the video published in an upcoming article where I compare Miracle-Gro Potting Mix to Home Microgreens Potting Mix by planting a quick-growing and slower-growing microgreen.

Thoughts on the Fertilizer

I’m not entirely against fertilizers. I’m not going to say you are nuts for using synthetic fertilizer or even fertilizer salts, but I won’t use potting mixes that contain them unless I’m caught in a pinch.

Maybe this will change once I finish my trial runs with Miracle-Gro. I’ll have to wait and see. I will also be researching synthetic fertilizers more in-depth in future articles. I’m leery of using them, but I still need an open mind. I’m not one to poo-poo something without proof.

Scott’s website claims Miracle-Gro is safe to grow vegetables. Here is a screenshot from their website.

miracle gro potting mix is safe for use on vegetables

We also have the dosage phenomenon where nothing is dangerous if the dosage is below a threshold, and I’d bet that would be the case for anything grown in these mixes that contain synthetic compounds.

So, if I had to use Miracle-Gro Potting Mix, I would because I believe the benefits of the greens or vegetables grown from it outweigh the negatives. That said, I won’t be using it unless I have to.

Results of the Scott’s Miracle Gro Potting Mix Test Growing Microgreens

When the results are in, I will post a summary here and link to the test article. I have Kohlrabi and Basil growing in the potting mix, comparing it to the same microgreens grown in the non-synthetic Home Microgreens Potting Mix.

I will also be filling in links when I publish short articles on the other ingredients listed in this article.

Below, you can grab my free ebook on how to grow microgreens or register for my Free Basic Microgreen Growing Course, which will sign you up to receive updates when major new articles are published to see the results of the above-mentioned test.

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The Home Microgreens Store has a full selection of competitively priced microgreen seeds, supplies, and equipment. You can support this blog, podcast, and small family business by visiting the Home Microgreens Store.


  • Todd

    Todd is the founder of Home Microgreens & the Home Microgreens store. He also writes for several other websites, including MyViewFromTheWoods.com. Todd worked at a large farm market, garden & nursery center for 20 years. Somehow he snuck off to become a geologist and professor before coming back to his senses to write & lecture about microgreens and gardening. When not at the computer, he can be found in the garden, trout stream, or mountain trail with his new Springer Spaniel Caden.

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