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.

• Choosing a raised bed design
• The benefits of gardening in raised beds
• Figuring out the depth of a raised bed
• How to make a new raised bed garden
• Inexpensive raised bed ideas
• The best vegetables to grow in raised beds
• Planting in a 4×8 raised bed