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One of the major benefits of gardening in a raised bed is you get to control the soil that goes into it. This is especially advantageous for gardeners with a property that has hard-packed or clay soil, issues with tree roots, or concerns about pollutants. It also comes in handy if you want to place your raised bed on a patio or driveway. Since good soil is the foundation of a healthy garden, you want to make sure you’re setting your vegetables up for success. So, what is the best soil for a raised garden bed? In this article, I’m going to share some advice on figuring out how much soil you need, what to purchase, amending a soil delivery, and more.
Another raised bed benefit is that the soil will remain friable. In an in-ground garden, the soil can become hard-packed over time as you walk between the rows. We know there is a whole web of micro-activity happening in our soil, so it’s best not to disturb it. A raised bed allows you to reach in to weed and plant.
How much soil do you need?
Filling a raised bed will likely require more soil than you think. A soil delivery might make the most sense economically. For my gardens, I’ve put a tarp out on the driveway and had soil delivered in a giant pile that my husband and I work at diminishing over time with multiple wheelbarrow trips. There are some great soil calculators online that can help you figure out the amount you need so you don’t over or under order. Anytime I’ve ordered a bit too much, I’ve added the soil to my other garden beds.
Another option I’ve taken advantage of is a bulk soil delivery in one big bag. This is much better than purchasing multiple small bags of soil. I have simply marked where I want the soil to be delivered and a forklift has deposited it in place. This option is a bit less messy than a traditional soil delivery. The soil is covered and protected from the elements, and there when you need it.
How to save a bit of money on soil
There are some ways to fill in the bottom of a raised bed so you don’t need as much soil to fill it. For example, if you happened to cut out the sod underneath where your raised bed will go, flip the pieces, grass-side-down to fill the bottom. There is lots of soil attached and the grass will break down over time—especially after you cover it in fresh soil. You could also add yard waste, like leaves from a compost pile or big branches and sticks.
Another option is if you’ve moved soil around to create a garden, you can use that for the bottom, provided you amend the soil on top accordingly.
The best soil for a raised garden bed
When I built my raised beds, I called around and ordered what I thought would be a good-quality triple mix. In Ontario where I live, triple mix is generally top soil, compost, and peat moss or black loam. A 50/50 mix seems to be more common in the U.S., which is a blend of top soil and compost.
If you’re ordering a soil delivery, try to find out where your soil has come from. Topsoil is often taken from land being developed for new subdivisions. It might have sat for a long time and can be devoid of nutrients. Make sure what you’re getting is a blend that will nourish your plants.
If you’re purchasing bags of soil, look for labels like organic vegetable and herb mix or organic garden soil for vegetables and flowers.
Whatever soil you end up using, you want to make sure you amend it with compost. All that rich organic matter is an important component that will hold moisture and provide nutrients to your plants. Compost is an essential ingredient in the best soil for a raised garden bed, no matter which mix of ingredients you choose.
I filled my beds with about 3/4 triple mix, and even though it had compost in it, I top-dressed the garden with about ¼ compost. If you don’t have a compost pile, there are all sorts different types of compost on the market. Garden centers sell everything from mushroom or shrimp compost, to composted manure or bags labelled “organic vegetable compost.” Your municipality might even have free compost giveaway days in the spring.
Amending the soil in your raised bed
If you don’t have a compost pile, keep some compost on reserve throughout the gardening season. If you’re pulling out your spent pea plants mid-summer, for example, not only are you removing a bit of earth, but those plants will have depleted the soil of nutrients. Topping up your beds with compost will add nutrients back into the soil to prepare it for whatever you plant next.
I like to add chopped leaves into the soil in the fall. Run them over with your lawnmower and sprinkle them into your beds to break down over the winter. I have a compost pile where all the other leaves go. When they’re ready, I’ll use the leaf mold to spread in my gardens. To maintain the health of even the best soil for a raised garden bed, adding organic matter every year is essential.
In the springtime, I also will amend the soil with compost and/or composted manure. I find the soil levels in my raised beds are usually lower from the weight of the snow. A spring refresh fills them back up to the top, adding lots of fresh nutrients into the raised bed.
Additional soil advice
- Discover the various organic garden soil amendments you can add to your raised bed.
- It’s a good idea to do a soil pH test from time to time, so you can make the necessary amendments that will help your crops to flourish.
- If you have smaller containers to fill, check out Jessica’s recipes in her DIY potting soil article.
- Learn the difference between potting soil and garden soil.
- Growing cover crops is also a great way to add nutrients back into the soil.
- If you are growing berries, like strawberries and blueberries, which like a more acidic soil, you can purchase soil that’s been specially formulated to grow them, or adjust the level with elemental sulfur or aluminum sulfate.
Tips for building and planting raised beds
For more information about starting a raised bed project, check out my book Raised Bed Revolution, and my course, Raised Bed Basics for Savvy Gardening School. Both cover the importance of choosing good-quality soil, as well as lots of other advice.
Hey Tara!
Just built (2) 4’X4’X16” raised vegetable boxes. I figure I need about 32 cubic feet of soil mixture for growing. What do you suggest?
We live in Southern California…
Hi Glenn, I generally recommend a 50-50 blend that is generously amended with compost. I also wanted to make sure that you have some tips related to your climate, so I found this article that might be helpful for you. https://www.latimes.com/lifestyle/story/2020-02-28/best-garden-potting-plant-soil-feed-loamy-peat-moss
I would also recommend adding mulch to your garden to help retain the soil moisture. http://mgorange.ucanr.edu/Soils-Fertilizers-Compost/?ds=547&reportnumber=1013&catcol=3821&categorysearch=Soil&catcol2=0&categorysearch2=
Hi
I am also building 2 raised beds 8ft x 4ft over existing lawn area
Is it absolutely essential to turn the sod over? I have read that its okay to put cardboard or damp newspaper over the grass then add soil? The beds are 22mm high
We have our own compost as well as 2 enormous oak trees so loads of leaves at our disposal every year
Is it okay to mix the compost and/or leaves with topsoil without adding anything else and in what order?
I’m putting my raised bed (8X4) X 12inch on existing lawn, is it ok to cut the lawn and leave the cut sod as base material and then fill the bed up with the topsoil and compost? I live in Florida with all year round sun.
Hi Clem, Absolutely! That’s a great way to build up the soil in your raised bed. I would cut the sod and turn it upside down in the raised bed before filling it.
Hi Tara
I also had a problem with cucumber beetles as well as squash bugs and vine borers. They devastated my cucumbers, squash and zucchinis which I grew in my raised bed and containers. My question is can the soil in my containers be reused to plant other vegetables or should it be thrown out. I am going to amend the soil in my raised bed but with the probable presence of pests can I safely grow root vegetables where the cukes/zukes were?
Hi Diane, Crop rotation is a good idea. You can reuse the soil, but I would amend it with compost. Planting root vegetables where your cucumbers were, if you’re rotating crops is okay. These are good companion plants, as well.
Hello Tara,
I’ll be using a raised bed for the first time soon, and I want to thank you and the people writing here answering a lot of my questions. What are some of the best ways to prevent earwigs and other hungry critters from eating the tender seedlings? Does copper tape work? I really do not want to make an elevated cover cover for this bed!
Many thanks in advance.
Hi David, I’ve only used copper tape to keep slugs out. This year, I put row cover over the raised bed that has my brassicas in it. I wanted to keep the cabbage moths – and subsequent cabbage worms away. But you can’t keep the cover on if you have plants that need to be pollinated. I had a big problem this year with cucumber beetles. I was out there every morning drowning them. This article might be helpful for other pests that frequent your garden. Companion planting can help attract beneficial insects, as well. https://savvygardening.com/guide-to-vegetable-garden-pests/
Can I layer straw mixed in the soil?
Straw is great as a mulch and will break down so that next year when you refresh your soil, you’ll be able to add it over top!
Hello! We have recently built a raised garden where I plan to grow veggies/herbs and maybe berries. I told my husband that we needed compost & top soil but he ended up purchasing top soil and bags labeled “compost & manure” which has cow and chicken manure in it. I am wondering if this is safe to use? We have equal amounts of both in it right now basically mixed together. Should we remove it all and go without the manure or add something else on top? Thanks for any help! 🙂
Hi Peyton, Cow and chicken manure are fine (and great soil amendments) as long as they’re well-composted, which they would be in a bag. If it’s mixed with the topsoil, that is totally fine.
I live in Ga and have red clay dirt so I’ve decided to do a 12×12 raised bed garden. I’ve read hours of info but still confused as to how and what. I have grinding from 4 tree stumps in my yard. Is that considered compost? If I use garden fabric is that over or under compost, then veggie soil then top soil? Appreciate any help for a newbie!
Hi Kennedy, I think your ground tree stumps would be more of a mulch. Depending on the depth of your raised beds, you could use this on the very bottom of your raised beds to fill them a bit before adding the soil. I would avoid garden fabric, unless you’re trying to keep roots or weeds suppressed. If you do use fabric, it goes under everything. I would mix veggie soil, top soil, and compost. (1/3 of each)
If I use potting soil with fertilizer do I still need compost?
Yes. The compost will help with moisture retention and add beneficial microbes that can help your plants fight disease.
HI Tara, I live in Ontario as well and was starting my first raised vegetable bed this year. Trying to keep an average budget, was planning to make my own mix and buy 50% top soil, 30% compost and 10% pea moss after doing quite a bit of reading since I am nervous about this going in the first time. Does the mix sound good? I also just read that peat moss once dried doesn’t rehydrate. Your thoughts pls… thanks!
Hi Ruchi, If you can find a triple mix, rather than top soil, that might be a bit better. Usually it’s a mix of top soil, compost and peat. I used about 70-80% triple mix for my raised beds and 20-30% compost. 🙂