The Square meter garden soil mix is a third each of compost, peat moss and vermiculite.

I have assumed that in the UK since most of our composts are around 50% peat moss I could just do: 2/3 compost and 1/3 Vermiculite.

It was recently pointed out to me that American English vs British English (AE/BE) might be using the terms compost and soil differently. I would just like to ask if my assumption on using 2/3 compost (50% peat moss) and 1/3 Vermiculite is ok?

NB: extra points for peat alternatives that work well in the square meter garden structure.

  • 1
    "square meter" gardening, eh? Interesting example of how there are sometimes only rough equivalents to translate to in another context. The US book was, if I remember correctly, "square foot gardening". But there are a little more than 10 square feet in a square meter and "1/10 of a square meter gardening" probably is just a bit too OCD for a book title. ;-) Sep 8, 2015 at 15:42
  • @irrationalJohn It's real, honest, SQM. I assume Square foot gardening is based on a 3x3 grid. so SQM is basically a 3x3 grid. I and if you build your square to be a meter on the outer dimension then probably left with 9 square feet on the inside. NB: None of my beds are square, 2x8 squares. So the whole square meter thing really went out the window for me.
    – Morgan
    Sep 8, 2015 at 19:31
  • 1
    I just read this stuff, well said, Morgan!! Giggles!!
    – stormy
    Sep 8, 2015 at 20:04

2 Answers 2


In the American English version of the book, it is clear that the recommended mix is 1/3 of mixed, composted materials. That includes things like mushroom compost, composted cow manure, composted poultry manure, and composted kitchen scraps. If this is similar to what you would find in a bag of compost in the UK, and if those bags are indeed 1/2 peat, I would say your plan of mixing 2/3rds compost with 1/3 vermiculite would get you a decent approximation of Mel's mix.

That said, I wouldn't worry too much about getting the mix exactly right. I think Mel has done a great job marketing his SFG method, but there are a lot of other gardeners out there who have experimented with intensive gardening, and it can definitely be done without that exact mix. The mix just ensures that every gardener following the system is starting with basically the same soil, so they are likely to get similar results.

A great (and much cheaper) alternative would be this:

  1. Get a soil test done of the soil that is currently in your raised beds. If you are building new beds, remove the grass for the beds and test the soil underneath.
  2. Amend the soil as recommended according to your test results.
  3. Start adding organic matter to your soil. You can do this by digging in any (or all) of the composts listed above.
  4. Plant according to the SMG recommendations. Add compost to a square each time you remove a plant.

You really don't need the vermiculite or peat in most gardens, in my experience. I live in an area with very heavy clay soil. I used Mel's mix in one of my beds just to try it out. My other beds were all built up as I described above. The Mel's mix box did not perform better than my other garden beds.

  • 1
    My understanding of the role of Vermiculite is to lighten the soil, root grow easier, and then main function is to absorb water and release water back as the soil dries. For those just starting out this helps limit drowning (over watering plants) and makes them a little more drought tolerant.
    – Morgan
    Sep 8, 2015 at 21:51
  • The my understanding of the function of peat is to also lighten the soil and provide water retention properties. But as you point out this alters the pH of the soil. I have ordered a pH tester so will not be so at least be able to under stand and control this aspect of it.
    – Morgan
    Sep 8, 2015 at 21:53
  • Yes, vermiculite loosens the soil and peat retains moisture. They are easy fixes for common garden problems, but soil that is high in organic content is light and retains moisture well, too. By all means, go for it if you like - I just wanted to make sure you knew there are other ways to get the same result.
    – michelle
    Sep 9, 2015 at 3:28

I agree with michelle...are you adding ANY soil to your mix? It sounds as if it is all compost or organic matter! Plants HAVE TO HAVE SOIL! And I gotta say NO WAY DO YOU USE GARDEN SOIL in pots/bags. Garden soil is a very large ecosystem. It is not perfectly mixed but in the larger picture it is better able to provide balance. There is NO WAY to shovel up a little chunk of this ecosystem and ensure balance for potted/bagged plants. ALWAYS use sterilized soil as a basis for pots and bags.

Making raised beds in your garden would be the best thing, Morgan! You can add compost as you double dig but after that you should never have to double dig again unless it is late fall or early early spring. Sounds like you are doing TOO MUCH OF A GOOD THING and a heck of a lot more work than is necessary or prudent.

I HATE vermiculite. Perhaps it is just the little white spots but organic matter makes ANY SOIL better and wonderful. In fact DECOMPOSED ORGANIC matter is the ONLY way to improve ANY SOIL. Somewhere on this site I have gone at lengths to explain. The only time I will ever use peat moss is to add acidifying organic material to soil. I love the texture and ease of peat moss but it also SHEDS water if it isn't mixed in well and certainly your amounts are way too much.

Have to add that there is this...'hippie' type guy I kinda knew in Seattle, WA. He made his own mix and was selling it to clients/followers/non-gardeners for $100+ per yard. Lots of pea gravel 's involved...for drainage I guess. What a waste of money!! He got rich 'making the best ever soil' as well as using his clients money to 'design' landscapes... but this is not correct management of soil! Out of all the soils I've had to manage, heavy clay did as well as yummy silt loam. I hate this sandy, porous pumice I am struggling to grow stuff in!! But all three; I use raised beds, I mix DECOMPOSED organic matter (compost) when I first double dig and fluff and create my raised beds with trenches along the bottom of these beds to direct excess water. I cover and keep covered with compost all year. Organisms eat this stuff and go back into the profile to POOP IT OUT. The decomposed compost feeds the organisms in the soil and their activity and poop support plants as well as making ANY type soil wonderful soil. DECOMPOSED is the important word here! Kitchen scraps, bark, rock...all are considered mulch. Compost anything that is organic. Compost should mean DECOMPOSED organic matter!!

Gotta stay with what you have for soil and learn the proper management for your type of soil. The ONLY proper way to improve garden soil is adding DECOMPOSED organic matter on top of your beds if they are already established. I've said this before but made a big impression for me as a gardener...if you've got clay and add gravel, gypsum, lime, water and agitate...what is produced? CONCRETE.

Get a soil test, take a mason jar and put a few inches of your soil in the jar and fill with water. Shake, shake shake and allow to settle. This will show you percentages of the different soils that make up your natural soil. Heavier sands will be on the bottom, silt/loam in the middle and clay on the very top. Organic matter will be floating in the water. I don't remember the percentages for labeling your soil but that is out there on the internet. Add to this a laboratory soil test...and you'll be able to make decisions about your soil/plants/garden/management practices that make sense for your soil...and much more chance of success!! You are definitely a gardener, Morgan! This information will FEED you!! Grins...

  • I was buying all of it in bags, not garden soil. but from 'Mels Mix' there is no soil. I understand why you by sterilised soil now though.
    – Morgan
    Sep 8, 2015 at 20:04
  • I just myself figured the mathematics here...there was NO SOIL. Amazing! How could anyone make BETTER SOIL without SOIL? Amazing. Oh I am glad you understand. Don't think I've been able to make this clear before...exhausting!! I surely would like to see you be able to grow potatoes...want to see your alliums!
    – stormy
    Sep 8, 2015 at 20:07
  • Will investigate soil kits, orignally though this was just for pH so have ordered an electronic soil pH tester. The garden soil is clay but I am on a new build site (housing estate) so under the 1cm of top soil there can be a lot of building waste. foil, nails, bricks etc. Trying to find pictures of alliums which are directly into the soil with a little compost thrown on top.
    – Morgan
    Sep 8, 2015 at 21:32

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