The best DIY soil mix recipe has been a long time in the making. This DIY soil mix isn’t just something I threw together on a whim and hoped it worked; I spent a lot of tireless hours researching this! I love this soil as a DIY potting soil and for my Square Foot Garden Boxes.
I’ve been using a combination of Mel’s Mix and potting soil on our little homesteading; and the results haven’t been horrible. But I wanted to take our garden to the next level. I wanted a DIY soil mix that would hold moisture, be full of rich nutrition, be lighter (less compaction) and more sustainable. The result is the best DIY soil mix recipe around!
The Best DIY Soil Mix Recipe
DIY Potting Soil and Raised Bed Recipe
I mixed mine up in a wheel barrow this time but this makes mixing a lot harder. It would be better to do this on a thick tarp.
10 gallons of coconut coir (What I used)
5 gallons of sifted compost (Hopefully you’re composting at home)
2 gallons of worm castings (what I used)
8 quarts of organic vermiculite (what I used)
5 cups of Azomite (what I used)
I like to mix in each ingredient at a time.
- So first I put down the coconut coir, then I added my sifted compost and used my hands to incorporate them together.
- I repeated that with the worm castings and vermiculite.
- Lastly I added the azomite (be careful not to breathe the dust in!)
Now it is ready for use or you can store it in a bin or bags. I like to keep a top on it so it won’t get too dried out.
Check out this side by side comparison. On the left is a popular store-bought raised bed soil and on the right is my mix.
Now, let’s talk about the ingredients and why I included them
Ingredient 1 – Coconut Coir
Coconut coir is, first, a wonderful peat moss substitute. Peat moss is not sustainable; we are mining and using it at such a high rate coconut coir that it cannot renew before we run out. Coconut coir is leftover from the coconut industry, that was thrown away. What coconut coir does is add a spongy quality that it going to help your soil retain moisture (it can hold 10x its weight in water). It doesn’t clump and will not degrade in your soil as quickly as peat moss either. It will as a dried brick and you’ll need to soak this in some water to re-hydrate it. If you have coconut coir left over, don’t throw it away! Just store it for the next time you make your DIY soil mix. I soak mine in a tub and break it up a little as I go.
Ingredient 2 – Worm Castings
Worm castings are an amazing natural fertilizer. What’s great, too, is that plants soak up its nutrients quickly so it can stimulate growth better than any manure or chemical fertilizer. It can even help a plant fight off diseases by drawing out toxins. Worm castings also improve the texture of the soil, help to increase drought resistance AND it promotes good microbial activity. The best way to get this amazing additive is to be vermicomposting with your own little worms. But it isn’t a project I have going right now, so I opted to buy mine.
Ingredient 3 – Sifted Compost
I love compost – it is basically free soil, when you do it yourself. This fertile soil builder is a must have for homestead gardens. I like to sift mine because I don’t need “uncooked” materials continuing to break down and heat up the soil (120 degrees isn’t unheard of in Phoenix).
If you need some help getting started with compost check out Compost 101. If you decide to buy it, just make sure you’re getting it from a reputable supplier that is using organic materials without pesticides or other junk.
Ingredient 4 – Organic Vermiculite
Vermiculite helps keep soil from compacting but it also great for water retention. I live in a desert climate so I want to have ingredients that help my soil retain water. If you’re in a climate that gets a lot of rain you might want to consider perlite instead. Both are great additives but vermiculite is more sponge-like. So depending on your climate, choose what suits your needs.
Ingredient 5 – Azomite
Azomite (pronounced ā-zō-mite) stands for A to Z Of Minerals Including Trace Elements. Azomite is going to give your soil a power punch of minerals. What’s great about Azomite is that it is a slow release. So while your compost and worm castings are giving the initial dose of good nutrients, Azomite is going to follow them. Also Azomite won’t burn you plants…even if you put a ton of it in there.
What’s even cooler is that Azomite has been shown to help gardeners to produce more fruits and vegetables (and bigger) per plant. And the minerals improve the nutrition for US! Winner, winner, chicken dinner!
If you want to read more about Azomite check out Azomite.com
I hope my mix will help take your garden to the next level – I am using this in both my pots and raised bed. It could also be a great amendment to already established beds.
Happy gardening my friends!
More Soil Helpers
HOW TO USE RABBIT POOP FERTILIZER FOR A BETTER GARDEN
HOW TO IMPROVE SOIL WITHOUT A COMPOST PILE
AWESOME SOIL AMENDMENTS FOR YOUR ORGANIC VEGETABLE GARDEN
HOW TO USE ORANGE PEELS FOR A BETTER GARDEN
I just have a couple of questions… How much does this DIY mix make… do you have a rough estimate? Is this being used in raised beds? If so, what size are they?
You know, I haven’t measured exactly but it fills up my wheelbarrow. I used the mix in my raised beds (4×4) and in my fabric pots.
how deep are you 4×4 beds?
Originally 6 inches but I am converting most of them to 12 inches deep now.
Would this mix work for self-watering (sub-irrigated) raised beds? I want to make sure roots get enough air as well as water and am not sure about using such a large proportion of coir to other ingredients? Your thoughts are welcome!
I haven’t used it in self-watering beds but you could lower the coir and mix in more compost.
The recipe as posted is for the 6″ bed, is that correct?
I’m a bit confused as well. Are you just spreading a thin layer on topsoil, or is this the soil you’re using in your garden beds exclusively?
As far as I can tell based on the recipe above, the volume that this makes is slightly over 19 gallons, which is equal to a little over 2.5 cubic feet. If it requires 2 blocks of coconut coir at (currently) $20 a block, plus one whole bag of vermiculite at (currently) $15, plus 2/5ths of a bag of worm castings at (currently) $26 per bag, then even without the azomite, the cost comes to:
(2*$20) + $14 + ($26 * 2/5) = $65 per wheelbarrow load, or $26 per cubic foot.
I looked for cheaper coco coir, worm castings, and vermiculite options and was able to bring that down to about $17 per square foot. I am relying on the assumption that you could find similar prices near you.
To add an inch of soil to a 4′ by 4′ raised bed, you would require 1.33 square feet, so $17*1.33 = $22.66 per inch of soil. If you want to add an additional 6 inches to a single 4’x4′ bed, it would cost you $
$136 per bed, not including compost (assuming you have enough of your own not to require store-bought) or azomite, (since I’m not sure how many cups are in a bag and don’t know the density, so I can’t calculate it).
That’s… really expensive. I’m sure it’s better quality than the garden soil available at the garden center or hardware store, but even the reduced price is more expensive than all but the most super premium organic garden soils that are available only online, and I suspect much of those prices cover shipping. Cut 50/50 with topsoil at $1.50 per cubic foot, you’re looking at $75 per bed for 6″, or $13.75 per square foot – but at that point, I’m not certain it’s still as good quality as store-bought soil.
I think it might make more sense economically to double or triple the volume of compost (free or cheap, and generally fairly loose textured) relative to the coir, and either use the the worm castings much more sparingly, or use them for side dressing throughout the season or for precision applications in the holes for transplants or seeds. Alternately, you could collect some earthworms from your property and plop them into your raised beds before planting time (with some light snacks such as coffee grounds and dry leaves) to put them to work generating castings continuously without adding cost. (Most commercial garden soil contain lots of worm eggs). Red wigglers are great for vermicomposting, but they’re a bit high maintenance in my experience, and with our southern heat, my compost bin would probably cook them alive. Soldier fly larvae are my compost buddies; they are so voracious in the summer that they turn scraps into poo in a matter of days, no brown matter required.
I think the ingredients are really fantastic and I’m definitely going to look into adding azomite – I just think that you might be able to cut down the cost significantly without sacrificing quality!
I like the way you think and I have used this as an enhancement in beds vs the soil for the entire bed. Your math skills are killer! Keep sharing your thoughts and ideas!!!!
Just in case anyone asks again for the details.
Everything is broken down by Cubic Feet.
Imperfectly Happy Soil Mix
Additive Measure Quantity Unit Price Ext Price Cu. Ft
Coco Coir Cubic Feet 1.6 $6.72 $10.75 1.6
Perlite Cubic Feet 0.27 $8.50 $2.30 0.3
Sifted Compost Cubic Feet 0.8 $5.28 $4.22 0.8
Worm Casting Pounds 0.32 $1.66 $0.53 0.01
Azomite Pounds 2.61 $5.00 $13.05 0.05
Cost Per Cu Ft $11.31 Yield 2.73 Cu. Ft.
Box Dimensions and fill cost
Height Width Length Qty Lumber Dimensions Cu Ft Soil Cost Frame Cost Total Filled Box Cost
5.5″ 4.0′ 4.0′ 1.0 2@ 2x6x8 7.3 $82.92 $22.94 $105.86
Wow, Bob, this is fantastic!!!
How do you measure a 10-gallon quantity? Do you use a 5-gallon Home depot bucket or similar, or is it more complicated than that? Thank you.
Yep, used my trusty 5 gallon orange buckets. 🙂
How many bricks or pounds equal the gallons in your mix?
Do you mean of the coconut coir?
Im wondering how much of the coconut coir do you buy to equal 10 gallons? Do you hydrate it first before you mix?
You’ll need about 2 of the blocks and yes you’ll want to hydrate it before you make the mix.
There is some discussion as to whether peat moss is sustainable and coir is more expensive. Also, there is a tremendous amount of peat available. Have you seen the YouTube videos by Larry Hall on the rain gutter grow system and kiddie pool system using the grow pots? He also has videos on worms. He arrives to make gardening easier. He has a diy mix, self-watering systems, and low maintenance.
So cool, love this. Thanks so much for sharing. Cheers.
I’ve been using azomite for a few years and used to buy the micronized azomite for around $40 to $45 a bag. It’s actually a good value. Over time however I became concerned about the dust. I know purchase granular azomite which is a tad more expensive however there isn’t any dust so it makes me feel better. I also add in green sand, rock phosphate and either bone meal or bone char with coffee grounds. Most of the additives I’ve borrowed from a article or recipie from a peony farm located in New Hampshire. You may have to adjust pH depending on your area or adjust if you’re gardening in either sandy soil or clay soil. I unfortunately have a bunch of the clay crap with poor drainage. If worried about drainage I would substitute possibly perlite for vermiculite in your mix since I’m not living in a desert.
Thanks again Tiffany!
Angela Miller
Hi Tiffany,
When you say to use compost, can composted manure count (such as cow) Have you ever tried that?
Absolutely! I use rabbit manure, because that’s what I have readily available.
Do you use biochar in any of your mix? That last for years and it keep getting better and better each year. Please email
No, but I’ve definitely heard great things about it. I may need to up my soil game and try it!
Thank you for this great recipe. I’m planning a garden this coming summer, and don’t have much experience. i look forward to upping my soils health (never gardened here before) and having a nice garden.
Thank you for this!! Do you know if altitude matters for soil mix? Do we need something more or less up higher?
I am not well versed in altitude and soil. But plants and vegetables require nutrients based on what is or is not in your soil. If you are going to use this mix exclusively, say in pots or raised beds, it should do very well. If you’re mixing it into the ground as an amendment you may need to run a soil test to see what is needed.
I put my raised bed garden together in a bit of a hurry. I followed your mix but I didn’t add the worm castings or azomite. Can I add these now? Or what kind of fertilizer/amendments do I add moving forward throughout the growing season? I’m rather new to all of this. My raised bed garden has basil, tomatoes, bell peppers, cucumbers, and a few dill plants. Thank you!
Absolutely – but you might want to wait until you harvest everything in the bed and then add it in for the new plants. If you decide to add it now mix with some of the soil first and then add to the top. Azomite is so fine, if you just put it on the top, it will blow away.
This is awesome! I’m definitely making this for my containers this year. I’ve been wanting to start using coconut coir anyway. so…perfect time to start!
I started using your recipe for my new raised bed and grow bags 2 years ago and love the organic nature and lightness of the soil.
This year I sent samples to the Extension for testing and it was lacking nitrogen. The extension recommended adding Blood Meal OR Urea.
Do you know how much I should add to your recipe?
I was thinking I prefer the organic of Urea instead of the blood meal, should I add the Urea to the soil for my seeds or will it be too strong for seedlings?
Thanks,
Erin in MA
I haven’t used blood meal but rabbit droppings and coffee grounds will also add nitrogen. I’m not sure on an exact measurement but I’d start with 2 cups per wheel barrel and see how your plants respond. Do you make your own compost? Add those things, banana peels and egg shells to compost can help to boost nitrogen there too.
This is amazing information! I have raised vegetable garden beds and I’m getting ready to start a flower cutting garden. Do you happen to know if this mix would work well in the flower garden also?Thank you!
Hi Candance – I have used it in beds where flowers are companions to my veggies and they seem to love it too.