How to Create Mel’s Mix

Posted on February 19th, 2008 by Emily

You may be asking “whose mix”? Mel Bartholemew is the author of All New Square Foot Gardening, and the founder of the square foot gardening method. He recommends filling your garden boxes with a special mix, instead of dirt. Here’s the mix, how much it cost, and the benefits:

The Mix

  • 1/3 vermiculite
  • 1/3 peat moss
  • 1/3 compost (from as many sources as possible)

This is done by volume. My garden beds were each 4′x4′ and needed 6″ of mix to fill them. 4×4x.5=8 cubic feet of Mel’s mix. I did three boxes, so I needed 24 cubic feet of mix, 8 cubic feet of each item.  Now, this amount did fill my boxes initially, but as I watered and the mix settled, I added more compost.

The Cost

I was able to buy the peat moss and compost at WalMart or Home Depot, but I only found the vermiculite at IFA Country Stores (Intermountain Farmers Association).

  • 2 large bags (3.5 cu ft) vermiculite, $18.00 each
  • 1 large bale (3.8 cu ft compressed, expands to be more) peat moss, $9.00
  • 8 bags (1 cu ft) compost, $2.00 each (average price)
  • 6 extra bags (1 cu ft) compost, $2.00 each (average price)
  • TOTAL COST (three 4′x4′ boxes): $73.00

The Benefits

Why not just use dirt? You can, but there are some great benefits to Mel’s mix:

  • Planting and germination–Mel’s mix is much lighter than dirt, and it doesn’t get compacted down because you never walk on it. This allows seeds to push through much easier, so you don’t have to be so particular about what depth you plant the seeds.
  • Root systems–It’s really easy for roots to grow and spread in Mel’s mix. I was surprised when I pulled up my lettuce plants, the root ball was so large, nearly the whole square came up with it. I just shook out the mix and composted the old plants.
  • Weeds–by this I mean, WHAT WEEDS! As long as you are careful with what compost you get, there are no weed seeds in your mix (unlike dirt). If a seed blows in, the mix is so loose it’s easy to tug them right out. Again, I spent less than 1% of my time in the garden weeding. As a side note, I made the mistake of buying Nutrimulch (turkey droppings), and had tons of bugs. I won’t do that again!
  • Drainage–with Mel’s mix, you cannot overwater! Mel recommends hand watering, but if you choose to irrigate, how do you get the right amount of water to each plant? Easy! I used a drip system, and watered away! Mel’s mix drains so well, you don’t have to worry about it.

When you use Mel’s mix, you don’t have to worry about what kind of soil you have, or amending the soil. Every time you plant a square, you add a trowel of compost. You don’t have to rotate where crops are planted, or do anything special, unless you want to.

Cost Savers

Mel’s mix can be more expensive, but there are several ways to cut costs.

  • First, I bought compost in bags, but you can go to your local recycling center and get a truckload for about $30.00. Depending on how many garden beds you have, this could really save you. Here are some compost sources in Utah.
  • Also, you can fill your boxes with straight compost. The only drawback to this is drainage–your plants can really get waterlogged if you don’t pay attention.
  • My suggestion is to do an alternate mix: 1/4 peat moss, 1/4 vermiculite, 1/2 compost. Since compost is the cheapest ingredient, this will lower the cost while maintaining the benefits.

In fact, this year I am doubling my boxes (building 3 more) and doubling my boxes (making them twice as high). For my existing garden beds, I will just add more compost. For the new beds, I will use my alternate version of Mel’s mix.

Mixing It Up

Mel recommends mixing this on a tarp–so that’s the method I tried. The biggest mistake was that I tried to mix 24 cu ft of material at once. It was so heavy I could not lift even a corner. I know others who have mixed it in a wheelbarrow, but I think this is too small a batch. Next time I am going to try mixing 8 cu ft at a time. I think this would work using the tarp method.

  • Pour compost on a large tarp. If you used several types, mix it following the instructions below before adding other materials.
  • Add vermiculite.
  • Add peat moss.
  • If it’s really dry and dusty, mist it down but do not get it wet (makes it heavier).
  • Mix by taking two corners of the tarp and pulling them over the tarp (like making a burrito) until all the material is close to one edge, lay the tarp flat. Then take the opposite two corners and pull the other direction, lay the tarp flat. Switch back to the other side and pull until all material is running down the middle of the tarp.
  • Now shift 90 degrees (so you are looking down the column of material) and repeat. Basically, pull north, then south, then north until it’s in the middle. Then pull east, then west, then east until it’s in the middle again. Repeat until it is uniformly mixed.

What did you fill your boxes with? How has it worked?

Filed under: How To

« »

11 Responses to “How to Create Mel’s Mix”

  1. jmmoore321, on March 5th, 2008 at 6:13 pm Said:

    I started with two 4×10 beds which are 12 inches deep. Filling with Mel’s Mix would have cost me a fortune! I did the truckload of compost method last year and had good success with my plants. I think the only downside was the watering issues. It was hard to know if I was getting the right amount of water. (I used a soaker hose which was kind of hard in itself). Anyway, this year I bought a few bags of peat moss and vermiculite and threw them into the garden beds along with some additional compost to fill the beds back up to the top. Once in the beds I mixed it all together with a rake. I’d say about the top half (6 inches) is comparable to your “alternative mix”. If the plants happen to develop deeper roots they will be stuck with plain old compost ;) I’ll keep you updated on how it turns out this year!

  2. sunslight, on March 16th, 2008 at 1:07 pm Said:

    The mix I use for growing under lights, is 1/3 each of peat, perlite, vermiculite. With the cost of all these going way up, I’m switching to about 1/2 peat and perlite, with a little virmiculite spread over the top of each planting to retain the moisture.

    Be extremely careful when adding peat into Utah soil, that is clay.

    Peat is extremely fine. It will bind with the clay and cause it to become harder. Which is exactly what you don’t want.
    Also, don’t mix sand* into clay soil. When the summer heat comes, you will have turned your garden soil into adobe.

    The best thing to do is add compost & lots of it. Avoid manures because of the salts.

    *Sand actually can be mixed with the clay. Clay really holds water and is quite good with nutrients but they get locked up and the clay, as you know gets very hard in the summer. Sand is great to break up clay, but you will have to use more sand that you can imagine. A mix of 10:1 by volume is not out of the question. So for every pot of garden soil, if you mix in 10 pots of sand, it will make the clay friable. If you want to do that much work, okay, other wise, if you have clay soil, stay away from both peat and sand, as soil amendments.

  3. Megan, on March 23rd, 2009 at 1:33 pm Said:

    I love your site! I’ve found it very helpful, and have already referred to it often. We’ve been trying to locate vermicullite in the Seattle area & are having a hard time. One garden store said we should be able to substitute perlite for it. Would the measurements/amounts work the same?

    Thanks for sharing your experience!

  4. Alan, on March 23rd, 2009 at 3:05 pm Said:

    Emily,
    Love your site. You mention in your Blog on How to Create Mel’s Mix that you plan on doubling the number of boxes and making them twice as high (12 inches vs. 6 inches) I was wondering why you wanted more depth. I am just starting out and interested in all things SFG.

    Thanks.

  5. Emily, on March 23rd, 2009 at 7:27 pm Said:

    Megan,

    You can use perlite instead of vermiculite. It’s not the same, but if cost or availability is an issue, use the perlite. I just built garden boxes for my friend, and we used perlite to keep the cost low. Use in the same proportions you would vermiculite.

    Just a note–since my boxes are extra tall (12″ instead of 6″), I have modified my Mel’s mix to be 25% vermiculite, 25% peat moss, and 50% compost. I find it’s enough vermiculite and peat to retain water and make the mix light and friable, but it keeps the cost down.

  6. Emily, on March 23rd, 2009 at 7:30 pm Said:

    Alan,

    I had several reasons for “upsizing.” First, I wanted to grow some root vegetables, like carrots and potatoes. With my double-rail gardens, I had great success!

    Second, I didn’t want to mow around my gardens, so I dug out the sod and covered the ground with weed mat, then gravel. the gravel gets REALLY hot, and I think the heat was stunting the growth.

    Finally, I find that as the season progresses the Mel’s mix compacts down and sort of sinks. I wanted to be sure I had a MINIMUM of 6″ of soil–that was hard to do when the maximum that fit was 6″.

    I just built garden boxes for a friend (watch for the post coming soon!) and used 2×10 boards. It was significantly cheaper than vinyl and I think 9-10″ of soil will work well for her.

  7. George, on April 15th, 2009 at 7:14 am Said:

    For those in the Salt Lake City area, I found my coarse Vermiculite at:
    Steve Regan Co.
    Sells coarse Vermiculite in 3-1/2 cu foot bags
    for $20@bag
    801-268-4500
    4215 S 500 W
    Salt Lake City
    They gave me a discount without me asking….$17.50 a bag.
    That was nice.
    Maybe they will give a discount to you, also.
    George

  8. hippygirl, on April 27th, 2009 at 4:42 pm Said:

    I am trying to avoid buying peat moss because of environmental reasons (shipped from far away, for example). What else can I use if I want to try Mel’s mix?

    What I did was potting soil and compost mixed together for two beds. For another bed, I’m using dug up sod on the bottom (my soil isn’t bad, so I don’t mind if the roots grow down into it), mixed with some potting soil and compost. I haven’t planted in this yet, so no idea how it will do. The potting soil and compost mix is working well, but doens’t seem very frugal. :)

    I think that mixing my own soil with some compost is going to be the most frugal thing, but maybe not the most fertile soil, at least for this season.

  9. rainberryblue :: tool time :: May :: 2009, on May 22nd, 2009 at 3:27 pm Said:

    [...] ground looked pretty good at the depth that I’d dug it. I just spread on a thin layer of the 1:1:1 mixture of peat moss, vermiculite, and compost/manure that I used for the raised garden beds, planted my potato pieces, and spread on another layer to [...]

  10. PatisPatio, on August 2nd, 2009 at 11:09 am Said:

    I visited my old( I mean very Old) church and their were just a handful of people there. I volunteered for the VBS..only 3 children in the group..but that evolved into 12 for the class. I suggested Mel’s sfg and the pastor was in agreement..So here I am, not a Gardner but an artist with beautiful pictures of veggies,flowers and salsa bringing this community together.Bringing children and old folks to an event that promotes growth in the community.I found You and Your site and look forward to all the help I can get. I was the corporate Facilities Artist that traveled to Park City Utah to paint their indoor parking levels ..so gardners pray for me and this venture. Pati Mills Winter Haven,Florida

  11. TeriS, on September 10th, 2009 at 4:58 pm Said:

    I found coarse vermiculite in the Los Angeles, San Gabriel Valley area at WHITTIER FERTILIZER CO, 9441 Kurse Road, Pico Rivera, CA 90660 (562) 699-3461. $18 also peat moss $17.50 and LOTS of compost and such

Leave a Reply