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The Science of Mel’s Mix™

Let’s say you gather all your materials to build a Square Foot garden and take the time to construct your grids. Then let’s say you opt to fill those beds with ordinary garden soil, maybe even mixed with some good compost. What do you think your odds are of having a thriving Square Foot Garden? The missing ingredient in this scenario is a little magic we call Mel’s Mix, and it’s arguably the most important part of the Square Foot Gardening method. Skip it or attempt to do a workaround, and your results simply won’t be as effective!

Now, don’t get us wrong — we love compost! But compost alone in regular garden soil will not provide your veggies with the proper amount of nutrition and drainage that they need to really thrive. So, let’s take a minute to review what Mel’s Mix is and why it’s so vital.


Here’s a question we’re frequently asked: “Why can’t I just amend my native soil and be done with it?” The answer is simple — you’re amending your native soil in the first place because it’s lacking something vital, and that subpar soil will always be in your growing mix no matter how much compost you heap in there. So why not fill those Square Foot Garden beds with the exact mix of ingredients that your plants need right from the very beginning?

Here’s what Mel’s Mix does for you and your garden that amended native soil has no chance of achieving:

  • It conserves water. You want your plants to have just the amount of water they need — no more, no less. And Mel’s Mix does an amazing job at both retaining valuable moisture while allowing for excellent drainage so your plants don’t rot.
  • It precisely feeds your plants. The addition of blended compost means that your plants get the nutrition they need without having to mix, measure and add fertilizers.
  • It requires no digging or double-digging. Mel’s Mix ingredients create an unbelievably loose soil texture that allows plant roots to grow and expand, without the need to bust your ground up and dig, dig, dig. It’s easy from the beginning!
  • It takes the cumbersome science out of your gardening experience. Ever heard gardening friends who talk about soil pH and enzymes and such? Do your eyes start to cross and glaze over? We hear you. That’s why Mel’s Mix is so easy — the ingredients are perfectly balanced so there’s no need to get an advanced horticulture degree to understand if your growing conditions are right. With Mel’s Mix, they are.


Mel’s Mix is a unique blend of 3 ingredients in equal parts — here’re links to YouTube videos explaining why we use them:

Blended garden compost: Mel felt strongly that high quality, blended compost was the most important ingredient in Mel’s Mix, because it holds all the nutrients your plants need to grow — without any added fertilizers! Blended compost has at least 3 but ideally 5 different ingredients, and you can make your own or buy it bagged. Listen to Rick Bickling explain the importance of compost in Mel’s Mix here.

Peat Moss for Mel's Mix soil

Peat Moss

Coarse Vermiculite for Mel's Mix soil

Coarse Vermiculite

Peat moss: This natural material is the result of vegetation that has been decomposing for millions of years, and it not only makes Mel’s Mix lighter, it improves its ability to retain valuable water. While peat moss is the preferred ingredient, acceptable substitutes are coconut coir and PittMoss. To learn more, watch Rick’s video about peat moss here.
Coarse vermiculite: Vermiculite is another natural ingredient that, along with peat moss, makes Mel’s Mix loose and retains water. Vermiculite comes in different grades or sizes, from fine to coarse — and what you’re looking to use in Mel’s Mix is the coarse vermiculite. And while you can use perlite as a substitute to create looseness, perlite does not hold moisture the way that vermiculite does, making vermiculite the hands-down first choice. See Rick’s video about coarse vermiculite here.


If you make your own blended compost, that one’s easy — you source it right from your own backyard! If you need to purchase compost as well as the coarse vermiculite and the peat moss, there are several reliable places to look:

  • Home improvement stores
  • Independent garden centers
  • Landscape supply yards
  • Feed stores
  • Online sources such as Uline


The ingredients for making Mel’s Mix are more expensive than regular soil and compost, but the initial investment pays off quickly. The only ingredient you will need to replenish regularly is the blended compost — and the vast majority of Square Foot Gardeners report (just as Mel did) that their Mel’s Mix stays loose for 7 to 10 years. Eliminate all the hard work, expense and mixed results of amending your soil year after year. Start with the perfectly balanced organic garden soil, Mel’s Mix.

If you find this blog informative, consider donating to the Square Foot Gardening Foundation. Your support helps us to continue providing tips, resources and the mission of Square Foot Gardening.  


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