The key to a productive raised bed garden is without a doubt the quality of the soil. And over the years I’ve honed in on what I believe is the perfect soil recipe. So in this article, I’ll share with you all the ingredients I use to create the best soil mix for raised beds.
Your biggest investment in the success of any productive garden is the soil. But it takes time to build quality soil at least several seasons, but the best soil it’s always a diverse mix of quality organic matter.
When initially filling your raised beds mix all the ingredients together and incorporate them well. The u.s. composting council recommends that productive garden soil should contain 5% organic matter by weight that equates to about 30% by volume.
When I came up with a soil blend for these highly productive beds as well as all the other gardens I’ve been working in over the years that recipe has served me incredibly well season after season.
When I start my beds I blend all the ingredients together and then just continue to top dress in subsequent seasons after that.
Here’s what I use to create the best soil mix for my raised beds
The bulk of my raised bed soil consists of high quality topsoil, about 50% by volume.
Next, I’m adding about thirty percent high-quality compost, while making your own would be ideal it can be a challenge to make enough to equal 30% by volume for large or multiple beds that’s why it’s good to find a reputable supplier of bulk compost.
I look for certified compost is designated by the US composting council, but if you can’t find that in your area just do your homework and find the best quality compost you can when buying in bulk or by the bag.
So after the first 80% of the volume is added there are several other great options to fill out the total.
I have six go-to favorites that I used to make up the remaining 20% of my soil mix.
1. Well-aged shredded leaves
Well-aged shredded leaves are a favorite. They’re free, plentiful and a perfect ingredient to supplement the total. They also break down beautifully when added to the soil.
2. Mineralized soil blend
Mineralized soil blend made a noticeable difference to the success of everything growing in my garden and I use it about twice a year.
3. Worm castings – vermicompost
Worm castings – vermicompost adds five times the nitrogen, seven times the phosphorous, and ten times the potassium than ordinary topsoil.
4. Mushroom compost
Mushroom compost is the byproduct of ingredients in which mushrooms grow, what’s leftover after mushrooms have been harvested. It contains about three percent nitrogen and potassium, a bit of phosphorus, and other bonus elements like magnesium and calcium.
5. Aged ground bark
Aged ground bark is a good carbon source, freshly chipped wood will Rob from rather than benefit your soil during initial decomposition. Ground bark brings a variety of particle sizes that can really work up your plant health.
6. Composted cow or poultry manure
Animal manure is high in nitrogen and other nutrients and makes a great supplement to your bulk soil. Just note I did not say horse manure, the risk there is that it may contain a persistent herbicide that doesn’t break down even through the composting process.
It can create a big problem in your garden for several years, so be safe. I avoid horse manure completely.
So that gives you six options to complete the remaining 20% and don’t get hung up on the percentages just use what you have and divide it into equal proportions and if you do that you’ll be well on your way to great garden soil and the most productive garden you’ve ever had.
Why you should use raised beds?
I think there are several answers depending on your situation for me the most important thing is that I get to control the growing medium. So the soil that goes in my raised beds I know exactly what’s in it. And maybe you have a garden that does not have very good soil, you’re having a really hard time growing things.
Well if you can either blend your own soil or buy a pre-blended mix to put in your beds it’s the perfect medium for growing your things and then you know like because what you ever your vegetables and fruit are growing in you know they’re sucking in nutrients and things from that growing medium and then you know what you’re putting in your own body and that’s really important to me.
Another really nice thing about raised beds is that you can get or build raised beds that are taller. So if you have back or knee problems you can bring gardening up to a level that’s comfortable and doable for you.
Because gardening is a lot of work, it’s a ton of up and down, planting, weeding, harvesting, it’s just it’s a lot on your body. So if that’s keeping you from gardening putting in raised beds that are taller is really really nice
And a couple of really nice benefits of raised beds is that they drain better because like I said if you’ve got really bad soil maybe it holds onto too much moisture and they’re much easier to maintain in terms of weeds.
They also enable a longer growing season because the soil in raised beds heats up a lot quicker in the spring you get several more weeks of growing out of them than you would straight in the ground.
And for me, this is kind of a purely aesthetic reason but raised beds tend to make a garden look tidy. You can lay it out exactly how you want it to.
What soil should you use in your raised beds
There are several good answers depending on the scope of your project. If you are a beginner or if your project is small I would just go with the pre-bagged raised bed mix Espoma’s got a good one. They’re easy to move around.
They are specifically blended for this application and you know your plants are going to be happy in that and I feel like if it’s a small project it’s still cost-effective to use bagged and if you’re a beginner it’s really important to use the right product and to keep it easy.
That way the more success you have. That first time that you’re gardening the more you’ll want to keep going and it’s just it’s so rewarding that way.
Now if your project is bigger if you’ve got a lot of raised beds to fill it’s not quite as cost-effective to use a bag. If you want to still do that go for it it is easier in my opinion to move bags around them to move bulk around.
But what I would do is call around to local businesses that the type that sells like bulk mulch or gravel, compost, oftentimes they’ll have a mixed raised bed mix. Ask them what’s in it.
I have used both good ones and bad ones we happened upon a really really great one. So I’ll share the percentages of what our blend is.
It’s 56% premium topsoil which is a soil that’s not heavy, it’s really lofty, it’s also free of rocks and weed seeds. So it’s really clean soil.
Then 34% cascade compost which we have a forest called cascade nearby and it’s basically just composted forest materials. So leaves branches wood things like that that have been through the composting process and then 34 % of the mix is made up of that.
And then the last ten percent is composted manure and we’ve had that blend in these boxes for three or four years now and it’s been so great my plants have done really well in it. It hasn’t compacted but it is important to continually add good stuff back in.
So you can add in good compost back in like the land and sea. You can add in your own compost that you’ve made at home which is great. I also add in a starter fertilizer the bio tone every time I plant a new crop.
And it’s just important because these are raised up kind of like containers they’re more moisture that receives, that soil receives rain, snow or from sprinkling, it can leach out nutrients so we just need to be mindful of adding those things back in to make our raised beds last really long and have a lot of success.
What you don’t want to use is some unknown source of soil maybe your friends have a pile well sitting around because they had a house built or something and so they’ve got this pile just sitting there free for the taking it’s tempting because it’s free but you don’t know if there are noxious weed seeds in there or if it’s ever been touched by chemicals.
And one of the major benefits of gardening and raised beds is that you know what’s going into your food so using organic things I think is really important.