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.
Compost is a mixture of decomposed materials. Manure is plain manure, or manure mixed with hay, wood chips, etc. Steer manure should be avoided (they feed the cattle salt to fatten them up, and the high content of salt is bad for your garden). Garden soil is probably a mix of ingredients–possibly dirt, peat moss, compost, fertilizer, etc. If you are trying to make this mix, get PEAT MOSS, VERMICULITE, and COMPOST (as many different kinds as you can find).
Define compost.
I have always mixed my own getting supplies from the Home Box stores, ie Home Depot, etc. and mixed them: 1/3 manure, 1/3 garden soil, 1/3 amendment.
Am I missing the bought by not using compost or is this a generic name for ………?
Thankd
Ken
S. Calif.
p.p.s please do not buy “weed block” when your neighbors rake and bag up leaves for you to simply pick up. as least now where i live (gainesville fl) everyone uses thick paper bags for yard waste instead of plastic. The bad news is that we are allowing a Incinerator to be built near by for power instead of building a biochar plant and doing more solar (which we are doing a lot of, in fact every city should do as we are doing(the German system)
so in a few years our yard waste plus added trees will be burned in this plant to make electric power.
instead we could turn 70% of the yard waste into biochar and use the other 30% for fuel to run the plant and make a little energy.
p.s. I’ve been making my own BIOCHAR & CHARCOAL for years now. it is the biggest 5000 year old thing to hit gardening. Look up Biochar!
and as far as mixing soil. I use several 7-12 gallon black plastic, planting pots. I add levels of mix in (a few inches of this and then a few inches of this etc), use a small shovel to mix, flip the own thing into the next planter and mix it again. simple, easy and everything stays in the pots until i need it.
People “buy” what some call “compost”? Amazing…………….I collect 300-400 bags of Oak leaves a year that people leave out for the garbage. Then i use grass clippings to compost them or simply use them on top as a heat and weed block (I live in a very hot area of Florida). i also dig down a couple of feet and add a layer which helps hold water and keeps other roots out. They are FREE and going to a LANDFILL, save them and use them. I also add Perlite and red clay to my mixture. I do use “raised” or square foot” gardens but i mostly make double to triple wide beds and fill the middles with leaves to decay, keep my steps from compressing the ground etc etc. till, i make a lot of them (raised gardens) for others because they do not have my tiller and I guess, the will to use a hoe like i can. Because my grandmother taught me to be country strong.
I think it’s best to kill the weeds (remove them) and then put down weed mat, and then put down soil. Soil 8-15″, depending on your situation.
Is it a good idea to leave weeds under, covered with something to kill them off, like thick plastic? How deep should the soil be?
my above ground is different than yours. I have 7 boxes 18″ wide by 16 ft. long by 8″ high. In these I plant tomatoes, sweet peppers, peas, green beans, carrots, and broccoli. I also have two boxes 2 ft. sq. by 8″ deep for zucchini and another squash that I alternate each year and one more box 3 ft. by 8 ft. for cukes All this is fenced in a 22 ft. by 50 ft. garden space. This supplies me with enough veggies for three families for the summer, me for the winter, and a friends restaurant with veggies for the summer. I started 15 years ago with mels mix and now short cut using Schultz’s potting soil good for 9 months of plant nutrients. I also add Mushroom compost one year and moo poo the next. Have had wonderful success so far but my gardening days are numbered as I just passed my 75th birthday. I start my plants indoors in nothing more than peat moss pellets and peat moss containers. Last year had 98% germination with seed purchased from j.w. jung seed company. Hope this post helps others. All my friends call me pops.
We tried sfg last year for the first time. With the help of a book and Mels mixture, we had a great little garden. This year we expanded and tried the local mix. I have to say the money we saved was not worth it. Had problems with weeds, root rot, even tried adding more amends and soil but was a disappointing season. Lots of work and the results were no where as good as last year.
Hi Emily,
I did Mel’s mix for my vegetables. Do you recommend putting marigolds in my planter to keep away certain bugs. I have put a chicken coup structure around it to keep cats and raccoons away.
Thanks
Jeannine
I think the softened water may be part of the problem, but it also sounds like it needs nutrients, especially nitrogen. Try fertilizer, either chemical or organic.
We have started the sqare foot gardening a year ago. Both years our tomatos, peppers, cabage and onions start to turn yellow after about 3 weeks. We water it with water supplied by the city and it also goes through the softener. Could you tell me what the problem maybe?
I don’t think the potting soil is a good alternative. I would probably go with the local compost.
So I live in a small town, no big box stores only an Ace Hardware. My question is thay sell there house brand compost with no info on whats in it. The other choice is FoxFarms Ocean Forrest potting soil. Can I substitute the potting soil for the compost?
Many thanks! You have been really helpful. I have enough mix from last year to replenish the beds that have settled – and then I’ll simply add a variety of compost in the successive years. Yeah!
Again, thanks – and I’ll bet that you have also helped other second year sfg gardeners with this advice.
If you have Mel’s mix left over from last year, you can go ahead and use it to fill the beds for this year. You’ll want to turn the soil since it settles quite a bit, and mix it well. If you don’t have enough to completely fill the beds, just add compost. The peat moss and vermiculite should last several years or longer–you just need to replenish with compost. Try to use as many types as possible (from many sources, chicken, cow (not steer), horse, mushroom, turkey, etc.)
I’ll be starting my second year of sfg and have a lot of Mel’s Mix from last year. Three questions:
1) Is the mix still OK to use after overwintering (I’m in MIchigan)?
2) If the mix is still OK, should I put a layer of it on my raised beds or just mix in some compost for this second year?
3) If the mix is OK, I figure that I should till it with the mix left in the beds from last year – right?
Hope you can answer this – I have not been able to find out about this anywhere else. The book only talks about preparing and using the mix for the first year of sfg.
Jackie–As long as there’s a bit of a slope, I don’t think the newspaper will be a problem. However, if the garden is in the lowest spot in the yard, you may have poor drainage.
Jacrav,
Compost is decomposed organic material. In the US, most compost is made of one main ingredient. So chicken compost is mainly composed of chicken manure mixed with tree bark. Because the bulk of the compost comes from one source, it provides limited nutrients to the plants. So I suggest combining as many types of compost as possible. They also sell good mixes that contain ingredients from several sources. These are ideal, but I still try to use a variety. I think of it as eating vegetables–broccoli is good for you, but if all you eat is broccoli you will not get the vitamins and minerals you need. A variety of vegetables is required.
Hello Emily
I intend to start a square foot garden but i am a little bit confused about the different composts necessary.
Here in France we call compost the stuff that comes from composting plants and TERREAU the different mixtures one finds in bags at special shops in which one finds compost and a lot of other different materials like see weeds horse manure worm manure etc! Now when different sorts of compost are recommended are the compost made out of different materials or do they correspond to what we call TERREAU or MIX for you,
I will appreciate your view of my problem in understanding of what I should do.
Thank you for your help
Jacrav
Starting my first SFG in an area with a lot ot grass & weeds. I thought I might lay down some pages of newspaper before I put down the weed block fabric to deter the weeds. My husband thinks this may affect the water drainage. Is this a good idea or not? Thanks for your help.
Yes, but it’s not the biggest bang for your buck. Pumpkins take up to 8 squares for one plant–compare that to growing 2 large tomato plants, or 8 squares of green beans, etc. I like having a nice area where my pumpkins can sprawl, and use my SFG beds for more compact veggies.
Can I grow pumpkins in SFG?
Emily, thank you so much for all of this information! I’m starting my first SFG and was beginning to panic bc I had no idea what to do about the soil…I am headed out now to by the mixing ingredients and can’t wait! I am building just a 4x4x12″ bed, and have actually raised it up and set it on a wooden bottom, (as a renter and a digging-dog owner, I felt this was the best way to start,) but I wanted to ask how you felt about this type of bed…should I drill the bottom for drainage?
Thanks again!
Brooks
mynext25years.blogspot.com
Doug–Each plant has different watering needs, and Mel’s Mix doesn’t guarantee you’ll meet that need, but can’t drown a plant like you can with regular soil.
do you still believe you can’t overwater with mel’s mix?
Miracle grow contains fertilizer, so that explains the increased growth.
I would add some mulch or compost + peat moss. Apply as thick as you can, considering the plant. If it’s one per square, you can even leave a little “well” by the stalk to water it. And if you have the means, you could build an irrigation system to water it more evenly.
Hi Emily,
I wish I’d found your site before putting my sfg together, but, oh well. I followed Mel’s Mix as strictly as possible and things are coming up nicely except that I can’t seem to water gently enough. The soil is SO friable it washes around when I water. I’ve used a cup and watering can, same thing for both. I am finding veggies growing in the wrong squares because the seeds washed away upon watering. This is annoying, to say the least. How can I make my soil more stable now that I have seedlings and small plants? Thank you!
I would test the soil to see what’s wrong. Normally you don’t need to test, but before you throw it all away, find out what is wrong and fix it.
Last year, I set up my first “square foot garden” following your recipe for Mel’s mix, and I had a successful growing season. This year, I decided to create another 4×4 sf garden, and I thought I followed the recipe fairly closely, although I used a different mix of compost. Almost all of the vegetables that I planted in the new garden have died. Any suggestions?
In Utah you can buy it pre-made, but it’s EXPENSIVE (like $10 for 1 cubic foot, I think). But many garden centers sell some sort of garden soil mix, which might be worth a try, for simplicity sake.
Hi there,
I’m just getting into SFG and super excited to try it out this year. I’m struggling with where to put the garden because we mostly get shade but we’ll start small and see how we do.
Can you buy “Mel’s Mix” already pre-made? Or would that be just too easy? I’m just wondering for convenience sake and for buying in bulk whether any of these materials come already mixed together?
Thanks!!
Stacey
Becky–I would ask the people who run the composting facility if it’s safe or not. I know we have local bulk sources like this, and some say it’s safe while others say it’s black gold and they garden in straight compost. I think you have a shot–the other MUST haves are seeds and transplants (for things like tomatoes and peppers that need more time than the season allows).
Thank you so much for your detailed website. I need all the help I can get since I have a black thumb.
I am hoping to get my first ever garden set up this weekend here in WI. I know that I’m already a little late in starting. I’m also trying to spend the least $$ possible. I can buy 1 yard screened yardwast compost from the county for $5. Is this safe to use? If so what else is a MUST to add to have a successful garden?
My bed needs to go on a hill since that is the only sunny spot in the yard. Any other advice?
Thanks Again
Kim–I just prefer to cut the cost a bit by using more compost. Those 4 types will be fine–I don’t know if cattle manure is the same as steer? Steer are fed a high salt diet, and the salt in the manure is not good for gardens. Ask if the same is true for cattle.
I find it nearly impossible to find 5 different types, I just do my best and count it good. 🙂
I recently purchased Mel’s book and it says to use 1/3 peat moss, 1/3 vermiculite and 1/3 compost. You seem to be suggesting to others here to use 1/4 peat moss, 1/4 vermiculite and 1/2 compost. What should I be doing? My next question is about compost. The only compost I can find so far is mushroom compost, shrimp compost, sheep compost, and cattle manure compost. I can’t seem to find a 5th type as suggested in the book. Do I really need a 5th? Are any of the ones I’ve found not good for a vegetable garden? Please advise.
Thank you!