Pro Mix Potting Soil Review (vs. Miracle-Gro)

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This year, I decided to try Pro Mix Potting Soil for my 2021 garden. Back in 2020, I got serious about gardening. The pandemic inspired many new gardeners to try a quarantine garden, and while I wasn’t new to gardening, I definitely dove back in head first. But after planting SO many seeds indoors, I noticed tons of gnats. So, I decided I needed a change from Miracle Gro.

I asked about favorite potting soil brands in one of my Facebook gardening groups and discovered a lot of gardeners actually don’t strictly use Miracle Gro potting soil! Some mentioned Black Gold soil and others mentioned FoxFarm.

Some serious gardeners talked about how they make their own DIY potting mixes every year. It sounds like it works out cheaper and involves a true labor of love!

Numerous recommendations poured in for Pro Mix Potting Soil, so I decided to give it a whirl.

ProMix Potting Soil Review vs. Miracle Grow Brand
ProMix Potting Soil Review vs. Miracle Grow Brand – Big bag of compressed Promix soil on our stone walkway

What is Pro Mix potting soil?

Pro Mix potting soil is peat-based potting soil designed for indoor and outdoor plants as well as seed starting and other garden needs. The ingredients are carefully selected to support vigorous growth, better moisture management, improved nutrient uptake, larger root systems, and healthier plants overall.

What is in Pro Mix potting soil?

The Pro Mix moisture mix contains Sphagnum peat moss (80-90%), natural coco coir fiber, perlite, ground limestone (for pH), mycorrhizae, and an undisclosed wetting agent. The organic garden mix contains a bit less peat but also includes Gypsum. Meanwhile, the Pro Mix All-Purpose Mix includes Canadian sphagnum peat moss, peat humus, perlite, limestone, and mycorrhizae (PTB297 technology).

What's in Promix potting soil - peat based potting mix
Promix potting soil is a peat based potting mix.

Benefits of Pro Mix Soil

I loved Pro Mix soil from the first time I tried it this year (2021). It is now my go-to potting mix for the foreseeable future.

Here are the best benefits of Pro Mix Potting Soil:

  • Clean – From the first time using it, Pro Mix Potting Soil just felt cleaner and higher quality than any other potting mix I’ve used to date. The mix just didn’t feel as dirty as traditional potting soil.
  • Affordable – The bag of Pro Mix ended up costing me about 40% less than the equivalent amount of Miracle Gro Potting Mix. The 2cu ft value pack saves money and includes a LOT of potting mix!
  • Compressed – Two cubic feet of potting mix fit into that bag of Pro Mix! It’s packed in tight to take up less space. The compressed potting soil limits packaging, resulting in 2x less bags per package.
  • Convenient Package – The convenient packaging has a sturdy handle and a boxy shape that fits well in storage when not in use. The Pro Mix bag also holds its form after opening, keeping your garage and other spaces neat.
  • No Gnats – To my pure delight, I didn’t notice any fungus gnats, fruit flies, or other pests emerging from the soil. It’s been amazing, to say the least.
  • Recyclable Bag – It’s always great to see a company making an effort to a greener lifestyle!
Holding some Promix Potting Soil to Show the texture and what's in Promix soil
Holding some Promix Potting Soil to show the texture and what’s in Promix soil

Where to Buy Pro Mix

I purchased Pro Mix Moisture Potting Mix (with the dark pink label) at the Pottstown Walmart two or three times now. It was not in stock at the Bechtelsville Walmart, but I will check there again in the future. It is difficult to find during the off-season (late fall, winter).

You can also check your local hardware or home and garden stores, like Home Depot and Lowes, as well as Amazon.com. If you go to ProMixGardening.com, you can also search for a store near you.

Pro Mix Soil Video Review

Here’s some Pro Mix Potting Soil up close…

Pro Mix Potting Soil vs. Miracle Gro Potting Soil

In my experience comparing Pro Mix Potting Soil vs. Miracle Gro Potting Mix, I found Pro Mix to be the superior product. For years I’ve used Miracle Gro potting soil and I will continue to use it here and there. As far as indoor gardening and seed starting, though, I will rely on Pro Mix as long as it’s available.

Lovely texture of Promix Potting Soil in a nursery pot with a green spoon
Showing off the lovely texture of Promix Potting Soil in a nursery pot with a green spoon

Here’s the breakdown of Pro Mix vs. Miracle Gro potting soils:

  • Cheaper – Pro Mix wins this category as the 2 cubic foot bag of compressed soil was only $12.88 at Walmart. Looking at Lowes or Home Depot, I’ve seen the same about of Miracle Gro mix for close to $20.
  • Better Quality – I enjoyed the texture, composition, and cleanliness of using Pro Mix potting mix far better than the Miracle Gro mix. As I write this, gardening season is currently over here in PA Zone 6b, but I can’t wait for seed starting to run my fingers through the mix as I plant tons of seeds all over again.
  • Value – I feel that the amount of Pro Mix provided in the compressed packaging is very fair for the cost and happily continue to be a repeat customer for this product. When Miracle Gro potting mix goes on sale, I will happily still buy it for my outdoor garden beds and containers.
  • Purity – When comparing Miracle Gro potting mix to Pro Mix potting soil, I felt the contents of both seemed to have good purity. However, I liked the look and feel of Promix better and also found less trouble with soil gnats (fungus gnats?). Promix may also be a good option if you are trying to avoid fertilizers already being included.

Sometimes I struggle with maintaining proper moisture for young seedlings. I don’t think I had as much trouble this year using the Pro Mix Moisture potting mix, but I’ll try it again for next growing season and report back.

Promix potting mix in a nursery pot - here's my review of this potting soil.
Promix potting mix in a nursery pot

Truthfully, I do like both brands and would happily use either in seed starting, filling flower pots or containers, and amending outdoor raised beds as needed. Both companies offer quality products, and it was a nice change trying a previously unknown, new brand and product.

What’s your favorite potting mix? Have you tried the comparison of Miracle Gro potting soil vs. Pro Mix potting soil?

Shout out in the comments below so we can track everyone’s favorite brand and experiences!

Happy Gardening!

Edited 12.14.21 to add video and update spelling of Miracle Gro.

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  1. I started using ProMix last year and I am hooked. Exactly as you described in your article. I believe Miracle Grow is messing with consumers and offering an inferior product while rebranding the good stuff and charging a higher price…no good. ProMix is my go-to potting soil for now. I’m exploring Coast of Maine via Amazon. Bought couple of bags when there was a price drop but haven’t used it yet.
    Thanks for a good article.

    1. Hi Helen,
      Great to hear from you! Thanks for taking the time to share your experience and comment. I am so in love with ProMix and will continue to buy it. I hope others will give it a chance. I haven’t tried Coast of Maine but will look into it and would love to hear your thoughts on it after you try it. So glad you liked the article – thanks for the feedback. Always makes my day when I hear from someone like you who took the time to drop me a line. 🙂 Happy Gardening!

  2. Hello gardeners, I have been using Pro-Mix for over 15 years. I have 2 small greenhouses (for fun) and I worked in a large retail green house way back in– well way back. I was recommended to Pro -Mix by commercial growers I purchased plants from and have used it ever since. You are so right it is economical, clean and consistent. My tip to share too seed starters is to use a thin layer of fine ground sphagnum moss on the surface when sowing and use it to also cover seeds. I use No-Damp-Off but I have also ground my own from long fiber used for orchids. When planting varieties that like cool germination this can prevent many rot, damp-off and bacteria problems. Pro-Mix drains very well and is very good to use with seedlings that do better with bottom watering, ie Vinca. Happy Spring

    1. Hi Susan,
      Lovely to hear from you! I am so glad you’ve shared the tip on sphagnum moss – I sometimes have issues with watermelon seedlings damping off. Your greenhouses sound amazing! Thanks very much for sharing your experience – loved hearing from you. Happy Spring!

  3. My fiancee’ and I purchased the 2cu.ft (two in one), bag of pro mix potting soil from our local Walmart last week (2/15/22). We transplanted a nice sized fiddle leaf fig, and also a nice sized schefalera (both were about 3-4 ft tall). We transferred them to large pots that measure 12 inches tall by 14 inches in diameter. We had enough mix to do them both and even had mix left. We had used some miracle grow potting mix the week before that repotting peace lillie’s. I definitely like the pro mix better, and it was cheaper, we paid $12.88 for the 2cu.ft. bag. I like the higher moisture content of the pro mix, which means less watering, plus the perlite is a must with the schefalera and the fiddle leaf fig. I loved the article, and look forward to reading more.

    1. Hi James, Nice hearing from you – thanks for taking the time to leave such a nice comment. Your plants sound beautiful and I hope they thrive for you and your fiancee! (Also, best wishes for your upcoming wedding!) I loved hearing that you liked the article and also that you had good experiences using Pro Mix. I was so happy when I found it – and love recommending it to others whom I hope will also find the same quality and performance. I couldn’t agree more – the $12.88 price tag is incredible for how far a single bag of this stuff stretches. Perlite is definitely key – excellent tip. Thanks again for your helpful and kind comment and I’d definitely love for you to come back to my site and share your feedback and insights anytime. Wishing you all the best! – Kate

  4. I’d like to know when people talk about especially liking the perlite, they don’t add more to Pro Mix right it already has perlite right? I’ve only been gardening & growing indoor & outdoor for 5-6 years & found Miracle-Gro not holding up to it’s standards-thank you!

    1. Hi Donna, great point! It’s easy enough to amend something you already like to make it better. Some gardeners have soil recipes where they make their own mixes depending on their needs. I hope to do this one day as well. In my experience, Pro Mix does already have perlite, although some may like to add more. I am constantly working to make the soil indoors and outdoors better – we have rocky clay so it’s a tedious job. 🙂 Happy Gardening!

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