DIY Raised Bed Soil Mix Your Plants Will Love
This is a tried-and-true recipe for a DIY raised bed soil mix that I’ve been using for over fifteen years. The combination of ingredients ensures your plants have everything they need to flourish.
It’s been a busy season at our little homestead! We’ve been working on a few projects which I’m very excited about. This winter, I ordered way too many seeds and had so much fun planning this year’s garden. I may have gotten a little carried away. Does anyone else get this way in the dead of winter when you’re pining for spring to come? All of my planning meant that we needed to add more raised garden beds to accommodate all the new plants I would be growing. We built six more garden beds and doubled our garden space.
Of course, once you build raised garden beds, you need to fill them with some type of soil. You can buy premixed soil in bags from home improvement centers or even purchase truckloads from local nurseries. You can try to find inexpensive or free fill dirt from neighbors or friends who have dirt left over from a project. In my fifteen-plus years of gardening, I have used a specific DIY raised bed soil mix for all of my raised beds. I keep using it because my plants grow so well with this mixture.
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Recipe for DIY Raised Bed Soil Mix
The recipe we follow to make our DIY raised bed soil mix comes from the Square Foot Gardening book.
It consists of three different ingredients: vermiculite, peat moss, and compost.
An equal amount of each ingredient is added to the mix.
What Are The Benefits of Each Ingredient?
Vermiculite: Holds moisture in the soil so it’s consistently available for plants to use. Source
Peat moss: Retains moisture and releases the moisture to plant roots as needed. It also holds onto nutrients so they aren’t rinsed out of the soil when you water. Source
Compost: Adds nutrients that are important to a plant’s overall health, prevents soil erosion, and helps retain water. Compost can also help reduce the number of pest and disease issues. Source
How Do You Calculate the Amounts You Need?
- Calculate the cubic feet of your garden bed. Example: 6′ long by 3′ wide x 1.5′ deep = 27 cubic feet
- Divide the cubic feet of your garden bed by 3 (because there are three ingredients) Example: 27/3=9 cubic feet
- In my example, I will need 9 cubic feet each of peat moss, vermiculite, and compost to fill one garden bed. The bags of these products will have the cubic feet printed on them.
Where Can I Buy the Ingredients for DIY Raised Bed Soil Mix?
You can often find these products at local garden & nursery stores. However, I have had the best luck at our local Farmers Exchange store. They sell vermiculite, peat moss, and compost in large bags, making it more economical when filling several beds at once. If you are filling a smaller area, such as for a small container garden on your patio, you can purchase the ingredients here:
How Do You Mix the DIY Raised Bed Soil Mix?
I like to use the lasagna method to mix the soil into my garden box. Start with a layer of peat moss, followed by vermiculite, and then compost. Use a shovel to mix the three layers together . Once that is well-mixed, add another layer of peat moss, vermiculite, and compost. Mix again with the shovel until all three ingredients are integrated.
This is hard work and takes a good amount of muscle! I split the work up into a few days and worked on it here and there when I had some time.
If you use this DIY Raised Bed Soil Mix in your garden, comment below and let me know!
Do you gris enough for canning with the garden beds?
Hi Sandra, I sure do! I grew 15 tomato plants last summer and canned a ton of tomato sauce. I also can green beans, pickles, butternut squash, etc. And if you build a trellis you can maximize space even more.
Can you use the same mixture for indoor potted plants?
Hi Lin,
Great question! I don’t use this mixture for indoor plants because it’s made specifically for the outdoor environment. Bagged potting soil mixes are made for indoor plants and are more lightweight which helps them retain moisture while also maintaining enough air space around the roots. This is important when they’re in a smaller container and space is at a minimum!
I already have dirt in my garden beds. I was looking for a way to add that would “refresh” the soil. Can I add this mix? I’d hate to remove everything from my four garden beds.
Hi Gina, Yes, you can add this mix to the soil you already have in your garden beds. Obviously the makeup of the soil will turn out a little different depending on what you already have in your boxes, but it should only improve with these added ingredients.
Thank you for posting this. The amazon link to the compost shows a bag listed in pounds, not cubic feet. It’s 7.9gal., 32-35 lbs. so how many bags of compost would I need to purchase to fill the same sized bed as yours?
Thank you!
Hi Anne, Great question! I did the math on this one and this is what I found. You need 3 cubic feet of compost for a 3x6x1.5 foot bed. 1 cubic foot = 62.41 pounds. You will need approximately 187 pounds of compost. Each bag is 32-35 lbs so you’ll need between 5 and 6 bags. I hope this helps!
When mixing you ingredients try using a large tarp, just pull the corners,then the sides, that is what I do when I need to mix my soil.
Do you add the same amount each year? It doesn’t seem you would unless you’re emptying the box.