Square Foot Gardening Soil
How to Create Mel’s Mix
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:
Mel’s 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. 4x4x.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.
- BULK COMPOST–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.
- PLAIN COMPOST–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 MIX (MODIFIED MEL’S MIX)–1/4 peat moss, 1/4 vermiculite, and 1/2 compost mixed in the box.
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–Tarp Method
Mel recommends mixing this on a tarp–so that’s the method I tried at first. 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. It might work to combine 8 cu ft at a time.
- 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.
Update
The second year, I “upgraded” by boxes from 6″ to 12″. This required more soil: 4x4x1=16 cubic feet. To keep costs down (especially for vermiculite) I created My Mix:
- 1/4 vermiculite
- 1/4 peat moss
- 1/2 compost
Here are the updated calculations: 16 cubic feet per 4×4 box
- 4 cubic feet of vermiculite $25
- 4 cubic feet of peat moss $11
- 8 cubic feet of compost $25-40
The other change I made is in the method of mixing. I didn’t like using the tarp method because I garden by myself, and it was cumbersome and heavy. Instead, I put some of each ingredient into the box, mix with a spading fork, and then add more. When it’s dry it mixes easily, you can almost “stir” it. After your’e done, soak it really good with your hose.
Go here for information on what to add to Mel’s Mix after the first year.
Don’t over-water, just two cups per plant or so. And if they are struggling, give them shade. I hope that helps. Just remember–they WANT to grow, so you just have to help them along.
Emily, please help! I put together a bed with Mel’s mix, then planted some of my hardened off seedlings. The next day the tomatoes and squash are wilting and only the peppers seem happy! Any advice on what’s happening? Thanks a bunch!
Rasa–your beds are 3.5 feet by 7 feet: 3.5×7=24.5 sq ft. Now multiply by 8″ (8/12=.67) 24.5 x .67= 16.3 cubic feet. So you will need roughly 4 cubic feet of peat moss, 4 cubic feet of vermiculite, and 8 cubic feet of compost.
Hi! thank you for your informative site. i have just purchased my 1st raised bed and am excited to start my dream of gardening. the bet kit I bought is 42″x84″x8″ so I am a bit confused how much of what i would need to fill it with Mel’s mix. if you could please advise i would really appreciate it thanks!
-Rasa
Kathy–go here! http://www.mysquarefootgarden.net/spring-gardening-checklist/
I am in year two of my garden. Do I need to do anything to the Mel’s mix before planting?
Koren–The Monrovia Organics Planting Compost sounds fantastic! I don’t know the price differences, but I would not hesitate to use that, add 1 part vermiculite to 3 parts compost. If you have access to manure, I suggest you add it to the garden in the fall, along with shredded leaves, grass clippings, etc. Let it sit uncovered for the winter months, and it should be decomposed enough in the spring. You can test it–bring a pot of soil inside and see if a bean will sprout. I don’t know why, but I read somewhere that this tests if it will hurt young seedlings. Then in the spring add peat and/or vermiculite as needed. You can tell–if you’re turning the soil and it comes up in big clumps, it needs vermiculite. If it is super loose and flyaway, it needs peat moss.
Hello Emily. First and foremost I love your site! It’s great! And now to my question. I am going to start SFG for the first time and I’m having a heck out time trying to find compost out here in small town USA. What I did find out in the city was is a product called Monrovia Organics Planting compost that contains 13 different strains of mycorrhizae and is made from compost, peat moss, composted bark, sterilized rice hulls, perlite, and sphagnum peat moss. Should I try that and mix it with vermiculite and call it good, OR, my other option is a product called Soil Pep which is made up of Composted Douglas Fir, Ponderosa Pine, Other Composted Forest Products. I don’t know what to do or if I need to be adding manure to it as well. What is your take on my problem? Thanks so much! If you have any other advise please share! 🙂 Thanks again.
http://www.mysquarefootgarden.net/spring-gardening-checklist/ #3
Hi! I’m in my 2nd year of SFG. What do I need to add to my soil this year? Thanks for all the inspiration!
Elizabeth–If you soil is fairly loose and easy to work with, and does not have too many weeds, I would not replace the soil. A much cheaper alternative would be to:
1. Test the soil (use store bought, distilled water). I might even be tempted to pay to have this done.
2. Just keep adding Mel’s Mix to fill the beds each year
If the soil test comes back with bad results (too acidic, too alkaline, complete lack of nutrients) I might start fresh. Otherwise, I think you’re fine just adding to until eventually you have great soil.
Mix as deep as you can without breaking your back. My beds are up to 14″ deep, and I can turn the soil with relative ease using a spading fork.
Peat moss is slightly acidic, so see how your soil tests before adding too much. You can find a source to test it at extension.org. Look up your local extension service, and they should be able to help. However, if you are adding it along with vermiculite and compost, I think you’re safe.
Carrots will grow in funny shapes if the soil is not very loose and easy to grow through. It twists and turns if it hits any obstacle. Mel’s Mix provides virtually no resistance. Also, read about vermiculite sources–there was a link to an online source in the comments.
Hi Emily, thanks so much for all the great information. I’m new to SFG but we are going to try it this year (last year just planted willy nilly, very close together, and ate what grew). We built raised beds two years ago which are fairly deep and I’m wondering how much of the soil I need to amend. The beds are 4’x7’x18″; 5’x5’x20″; and 3’x4’x11. The smaller bed we’ve just used for herbs and I’ll likely continue that (so may not amend that bed so much).
We live in Los Angeles and have clay soil so we filled the beds originally with “clean dirt” we purchased, plus peat moss, manure, an organic compost blend from Home Depot, some sand, and I think some Ironite. I know we didn’t soak the peet moss so that might be an issue. I wonder if I should dig out all of the current blend and start fresh, aiming for Mel’s mix if I can find Vermiculite (which doesn’t seem to be available at a price we can afford right now — so maybe Perlite).
We have to dig it all out anyway to line the redwood beds with plastic sheeting (we didn’t think to do that originally) so I’m open to starting fresh, or just working with what we have.
1) How deep should I do the mixture? All of the soil in all three beds? Or can I leave a few inches of the current blend on the bottom and just do 12″ of Mel’s mix?
2) Do you think we should start totally fresh with new dirt, peat moss (we have a lot left over) and Vermiculite? Should I have the current soil tested and go from there? Add lime if it’s too acidic? Not sure where to get tested in Los Angeles, and home kits are not advisable b/c of the water pH, right?
3) Either way I’ll be adding fresh compost (however many kinds I can track down) — and if I added only that, how far down should I be turning the soil?
4) I think it’s probably advisable to add soaked peat moss either way to keep the soil fluffy, yes? Can I overdo it on the peat moss? If it’s already in there will it hurt to add 1/3 more?
We will be growing lettuce (a lot), tomatoes, beets, greens, herbs, carrots, peppers, cucumbers (draped down over the side), berries, and a few other things. The carrots were quite warped and odd shaped, but maybe that’s how carrots always are. Wasn’t sure if it had something to do with the nutrient content. The peppers did not grow (will try the egg shells) and the tomatoes just okay. I soaked with a hose to water, and often the soil seemed dry underneath (just 1 1/2 inches down). I think we may have had some of the city mulch in the mixture too so that might be why?
Thanks so much for any information/feedback. I know I have a lot of questions, so even just a little guidance is much appreciated!
Lisa–You don’t have to find mushroom compost, just do the best you can to have as much variety as is available.
Hi Emily ,
I am starting my Mel’s Mix, I just purchased 4 different types of compost which our chicken compost , worm compost , and two differnt plating soil mixs’. I am having a problem finding mushroom compost. Do I need the mushroom compost or can I use any other kind, if so can you reccomend some for me.
thank you
Peat moss is non-renewable. Sphagnum peat moss is renewable.
I am a NEW gardener and trying out a 4’x12′ bed to start this year. Have been doing lots of reading and did the lasagna method to prepare the soil. I put by raised bed kit together and it’s 6″ high. I laid down cardboard to cover the grass along the entire bottom of the bed and wet it well. I then added a layer of composted manure, a layer of last year’s grass clippings, a layer of coffee grounds and veggie scraps, then wood ashes, more manure compost, more clippings, and then topped with peat. All together, it’s 6″ deep. I wet it and then covered it tightly with a tarp to “bake”. I few weeks before planting, I plan on putting down 24 cubic feet of Mel’s mix. My concern is that the bed may not be deep enough. Can I just cut out a hole in the cardboard layer when I plant things like tomatoes and carrots? Stumped. Also, live in Maine and wondering if I should be safe planting Memorial Day weekend. Thanks!!
Maureen–I am not sure, but I would not be surprised if you can’t get Mel’s Mix locally in your area. I would try contacting a nearby ag or farmer’s co-op, and see if they carry anything similar. Another option you might consider–try pairing up with someone who has the mobility and ability to go buy and mix the ingredients, and you cover the cost, or at least a portion of it. When I started out I felt VERY pinched on my budget, and would happily have helped someone out in trade for a discount on materials.
Is soil humus with manure a good compost material in making Mels mix?
I forgot to add in my previous post that I like in Milwaukee.
Thanks for any help.
Is there any place outside of Utah that I can purchase Mel’s Mix rather than make it myself? I’m disabled and will find it difficult to do all of the mixing myself.
Rhonda–I found this definition: “humus, nonliving, finely divided organic matter in soil, derived from microbial decomposition of plant and animal substances.” That combined with manure would be great compost.
Karen–where do you live? I’m surprised to hear they don’t have peat moss at all. I would check Wal-Mart, Home Depot, Lowes, and a local nursery, and the farmer/ag coop for your area. You can use coconut coir, but the reports are it’s not as good as peat moss.
hi Emily! thank you so much for this wonderful site! i have a question , my are is very dry , and we have water restrictions , in the garden centers they dont sell peat moss , what can i put if a can’t find it?
thank you so much!
Jenny–Yes, I used a weed barrier when I started my gardens, at the bottom of the bed before I added soil. I did not use it on top to block weeds from growing.
So am I correct that you have raised garden beds full of regular soil, and you’re wondering where to go from here? If you have a lot of weeds, you might want to start over with new soil–that’s up to you. It’s somewhat a matter of cost and work. One of the benefits of this type of gardening is NO WEEDS, so if you can afford it, I’d start fresh.
Honestly, I’m probably too cheap to do that, so I might choose to test the soil to see its pH. If that is good, I would just add peat moss, vermiculite, and compost to what you currently have, mix it well, and see how it goes. Definitely add fertilizer to the garden before planting.
Jackie–Sphagnum peat moss is better because it comes from a renewable source (sphagnum) instead of from bogs of peat.
Should I use peat moss or sphagnum peat moss? Thanks Jackie
I LOVE your site! I’m going to try the SFG method this year, I put in raised beds 2 years ago but have had poor results and came across the SFG method and decided to give it a try. My question is for weed control I have a lot most likely due to poor soil originally put in the garden. Did you line the ground with a weed barrier first? Is it completely necessary? I guess where should I start from here . . . am I OK just adding 6″ of Mel’s Mix to my current soil? I’m hoping to make some “winning salsa” from this years crop!
Thanks for your help.
It sounds like your soil is not soaking the water in–strange! I would try doing something like poking holes all the way to the bottom, and water well.
Kristy–To refresh your soil just add compost, as many different types as you can. Be sure to “fluff” the soil first, because I always do and I don’t need to add as much as it seems at first. Peppers require eggshells. Not kidding, I save mine, dry them, then put about 5 dozen in a 5 gallon bucket and fill with water. Soak 24 hours, then water peppers and tomatoes–they LOVE it!
You can use steer manure, it’s just not the best. Mix it with chicken, turkey, mushroom composts. Sprinklers are okay, but not as good as drip irrigation. I’d consider adding fertilizer since you had a low harvest.
I have been using mels mix for about 5 years but what is the best way to renew when it is time to replant? My beds and 10-12 inches high and about 1/2 full. Should they be full to the top? Also do Peppers require something specific to thrive. Mine never grow. Also my beds are a little big slanting downwards. What would you recommend that I plant in the lowest sections?
If I bought Stear maneur is it a absolutely do not use it or if I use it and only use one bag per 4×8 will I be ok? Should I dilute it with something?
One more thing. My husband build sprinklers for the garden, it that a no-no? Should I be flood watering 2-3 times a week instead? He built them last year and the harvest was so low so I wonder if they are getting enough water?
Thanks for all your help!
Hi Emily,
This is my first year gardening with raised beds. I got my first bed ready and have planted a spring crop in it. When I water it the soil on top is very wet but below the surface the soil is still very dry. Even if I water it a lot the lower soil is still dusty dry. What’s going on? Did I mix wrong? My mix I used was 1/2 compost, 1/3 peat moss, and I toped it off with top soil then mixed it all together. I know it’s not Mels mix but I don’t have a lot of money to work with and that is what my husband bought. Thanks.
IFA in American Fork has the vermiculite I was looking for. I have a new 4×8 SQFG and it is made with Vinyl “Ranch Rails” from Home Depot. That means two rails stacked on top of each other for an 11″ deep box. We bought 3 3.8 cubic foot bags of peat, 5 bags of compost that were 2 cubic foot bags and 1 1cubic foot bag, and 3 of the 3 bags of vermiculite that were the large 3.5 cubic foot size. I thought that would be enough to mix up about 32 cubic feet of Mels Mix. We mixed it batches with one bale of peat, one bag of vermiculite, and a couple of bags of compost. This was about as much as two people want to handle. We used the tarp method and still had to shovel the mix into the garden box because it was too heavy for the two of us to just lift on the tarp. We did two batches and filled the box! We have watered it in to see how much it settles, and I am wondering if anyone has any comments on how much settling I should expect.
I DID call the local IFA store and they do sell the Mels Mix in 2 cubic foot bags for about $18.00 each.
Thanks Emily for your great site, blog, videos, and gardening insights!
Dan–Here’s the math:
4′ x 11′ x 12″=44 cubic feet
You will end up with 1/4 peat moss and 1/4 perlite and 1/2 compost (10 cu ft, 10 cu ft, 24 cu ft)
A cubic yard (3x3x3) is 27 cubic feet, so it sounds like you already have 32 cubic feet of compost, which is MORE than enough. Consider combining the composts and saving some for fall or next spring. You can bag it up in the same bags the steer manure came in.
Quick note–steer manure is not the best, because they feed steer salt to fatten them up. So the manure tends to be high in salt. But with your yard compost and worm compost (WONDERFUL!), I think your mix will be fantastic. If I were you I’d maybe add some chicken or turkey manure, and call it good. Perlite is the best substitute–not as good as vermiculite but it will do just fine.
I am going to try SFG this year. I have a 4′ x 11′ raised bed 12″ deep.
I have on hand 10 cu.ft. of peat moss and 10 cu.ft of perlite. Can I substitute perlite for vermiculite?
I have been composting my yard waste for several years and have 1/2 a yard of clean compost. I have another 1/2 yard of compost from a worm farm I use to dispose of kitchen waste. I also have 5 cu.ft. of steer manure. Should I get any kinds compost?.
Julia–check out this post on fertilizer. I’m going to be researching/writing more about compost too.
Also, some organic tonics.
What would you recommend as a good organic fertilizer?
Julia–I’ve never heard of doing this. I imagine it might work, but you’d definitely need to “feed” the veggies with fertilizer (organic or chemical).
Hi Emily,
I want to try SFG this year and I’d like to make the beds 10 – 12 inches high (for carrots, leeks etc…).
I seem to remember reading somewhere that it is okay to fill them half way with sand and then to just use Mel’s mix for the top 6 inches”
Do you think this would be okay? It would certainly be a lot cheaper.
G–so comment may be obvious, but there is something wrong with your garden soil mix. So tell me more–where did you get the compost that you originally put in your garden boxes? Was it all one type? From one source, or many? What type? Then, when you added peat moss and vermiculite, how much did you add? What proportions would you say you have? (1/2 compost, 1/4 peat, 1/4 vermiculite?)
I also live in a windy area, but with a little support the plants can grow just fine. I like to stake my peppers, and when I grew corn I had to support it since they have shallow roots and the soil mix is very loose compared to “dirt”. But if the plants are withering away and dying, the wind is not the problem. I would suggest that if you’ve used the compost for several years and never replenished it, it’s probably been quite depleted of nutrients.
Provide some more details and I’ll offer some suggestions. You can take your soil to be analyzed at a local county extension office, but I found out it can cost up to $50 in my area.
My garden boxes are full of compost already. We tried straight compost for a few years but hardly anything would grow in them. Maybe too acidic? so I added the vermiculite and peat moss. I still have a hard time getting things to grow. They seem to grow much better in just the plain dirt but I already have the compost mix in all of my boxes so now I don’t know what to do. I live in a high winds area which might add to the problem. Maybe the compost mix isn’t sturdy enough to support the plants. They get smaller and smaller and then are just gone. Sometimes the deer eat them and sometimes they get bugs but it’s so frustrating to spend so much time and money and have everything die.
Yes, you will need 16 cubic feet total, which would be about 4 cubic feet of vermiculite, 5 cubic feet of peat moss, and 7 cubic feet of compost. Or, I prefer a 1/4, 1/4, 1/2 mix with mine (heavier on the compost). Just keep in mind your goals when you go to the store. You want to find Vermiculite in large bags–I think I buy mine in 4 cu ft. each. Your peat moss will expand once you open the bale, so you can get away with buying less than 5 cubic feet. And usually compost comes in 1 or 2 cubic foot bags.
I just built a 4’x4’x12″ raised garden box. I want to use the Mel’s Mix and am a little confused on the 1/3 of each ingred. My caculations work out to 16 cu ft but would like to know how many bags of Vermiculite, Peat Moss, and Compost I need… Can you help or guide please???
You can make your own compost with grass clippings, fruit and veggie scraps and peels, and leaves. But most compost you purchase will have some form of manure in them. I’ve never heard of any risk of e coli, though I do not let my little ones “play” in the dirt when they are too young to understand that they must go straight in and wash their hands.
Compost–as many kinds as you can find, just to “top off” the beds.
I started last year with a mel mix. What do i need to add to it this year for fertilizer?
HELP! I am VERY new to gardening. I am just getting my garden started, (built my box this past weekend). I will be buying bags of compost most likely. What type of compost should I be using?. Is it dangerous to use a compost with animal manure due to e-coli contamination? I have small children who will be gardening with me. Does compost without non animal manure exist? Is this a stupid question?
3 is better than one–I don’t sweat this too much, just do your best to get a variety. And make sure it’s cow manure, NOT steer manure (contains a lot of salt).
I can only seem to find 3 compost sources instead of the recommended 5. Will this be a problem? I have found, forest, mushroom and of course cow manure.
Yes, you sure can. The deeper the beds, the better–but you have to offset that with the amount of work and cost of filling with soil.
Emily,
You’ve probably already answered this – but I’ve looked and can find anything. Can I dig an extra large depression inside my garden box? Would there be any disadvantages in dong this? I’m thinking it could give me some additional root depth for deep-rooted veggies without having to build taller boxes.