When we started our backyard garden, we knew we wanted to use raised garden beds because we didn’t want to revitalize the hard clay in our native soil. The beds allow you to customize the soil for specific plant needs, and the elevated 17-inch height makes it easier to tend to plants.
However, filling a raised garden bed can quickly become expensive. A garden bed that measures 3.5 ft x 6.5 ft x 17 inches is 32 ft3and filling this bed exclusively with high-quality potting soil, like Fox Farm Ocean Forest and Happy Frog, can cost $262.50 total, including weed barriers and mulch, or $8.20 per ft3. Note that these prices are based on our Southern California location and preferences, so they may change depending on where you live and what you prefer to use in your garden.
We aimed to fill the garden beds and reduce costs as much as possible. After researching various websites, books, and forums, we learned about traditional farming methods, like Hugelkultur, where you use local materials and resources for filling garden beds to reduce costs and create a more sustainable garden.
Most plants need at least 6-8 inches of rich soil to grow and develop a good root system, so we could grow vegetables like cauliflower, tomatoes, eggplants, lettuce, peas, and peppers as long as we filled the top 6-8 inches of the beds with rich soil. To spend less money filling the bottom half of the bed, we use the Hugelkultur method.
Cost of filling a raised garden bed
The total cost to build and fill five new 17-inch raised garden beds is $1,543.64 ($308.73 per bed). Here is a quick breakdown of how much it costs to fill five new garden beds with a total area of 135 ft3 using the Hugelkultur method:
| Item | Price per unit | Units Purchased | Price for 5 beds |
|---|---|---|---|
| Vego Garden 9-in-1 (17-inch) Raised Garden Beds | $168.22 | 5 | $841.10 |
| Burlap | $2.58 / yd | 13 yd | $33.54 |
| Wood logs | $162 (1/4 cord) | 1 | $162.00 |
| Straw bale (~46″ x 23″ x 15″) | $30.00 | 1 | $30.00 |
| FoxFarm – Ocean Forest (1.5 cu. ft.) | $11.50 | 23 | $264.50 |
| FoxFarm – Happy Frog (2 cu. ft.) | $12.50 | 17 | $212.50 |
| Fine straw mulch | $ 33 (2.5 with. Ft.) | 1 | $33.00 |
| Total | — | $1,543.64 |
Disclaimer: The prices above reflect our local Southern California prices. Some items above can’t be easily divided into a single garden bed, such as hay bales. We also received volume discounts for wood and fine straw mulch.
Preparing the raised bed
Before filling your garden bed, determine where you will plant in your backyard or space. Measure the size of the garden bed to ensure it fits before assembly. We used websites like Shademap to help us figure out the best location that gets the appropriate amount of sun during the day.
It’s essential to level the ground so the bed is flush; otherwise, soil can leak out.
Assemble the raised garden beds based on the instructions on the package. We used Vego Garden 17-inch-tall classic metal raised garden beds and assembled them over several days.
Place the bed in the planting area and line the inside of the bed with a weed barrier. We used natural burlap, but you can also use flattened cardboard or weed barrier lining. If your area has gopher issues, I suggest lining the bottom with chicken wire.
What is hugelkultur?
Hugelkultur is a gardening method that utilizes nearby organic materials to create a healthy and sustainable garden. It comes from the German words “hugel” meaning hill, and “kultur,” meaning cultivation. Initially used in European forests, people would layer felled, rotting trees, branches, and other compostable materials in a mound that would eventually decay into the earth, improving the soil over time.
These days, many backyard gardeners use a simplified hugelkultur method in filling raised garden beds to offset upfront soil costs and benefit soil health in the future as the plants grow. I’ve seen gardeners use wood chips, dried leaves, and compost for the bottom half of their beds.
Not everyone has access to rotting logs or composting materials, so hugelkultur is just one method. Options for filling don’t have to include soil or natural material. Vego Garden sells a filler for their tall beds, which is called “Soil Saving Floor,” and it is said to reduce over 50% of the soil needed for beds that are 32 inches tall.
We needed to fill 135 cubic feet across five new garden beds. We used a similar hugelkultur method utilizing local materials such as dried logs, branches, straw, high-quality potting soil, fertilizer, mulch, and other amendments. With this method, we paid $747.54 total (or $5.53 per ft3). We saved 30% of money using this method compared to filling the beds exclusively with high-quality soil, which would have been $1,063.05 (or $7.87 per ft3).
The bottom layer: woody materials
Ideally, it’s best to use rotten wood for the bottom layer because it has a faster decay process, and as it breaks down in the soil, it won’t take away any nitrogen to break down. However, not everyone has access to rotten wood, so we used dried, seasoned wood from a local wood shop and fallen branches from our backyard Alderwood tree.
You can use a mix of soft (like Alderwood or pine) and hardwood (like oak). Still, some hugelkulturists and botanists believe that certain species, such as black walnut, release an allelopathic chemical that can inhibit the growth of nearby plants. There are ongoing studies on allelopathic trees, but we generally try to avoid them.
This bottom layer should cover about 30% of the garden bed. Since we didn’t have enough wood available in our backyard, we purchased ¼ cord (or 32 ft3) of dried wood at a local firewood store to fill all five beds for $160. For one 3.5 ft x 6.5 ft x 17 inch bed, we needed almost 5 ft3 of wooden logs, and it cost roughly $25 per bed.
The middle layer: compostable, organic materials
In the next layer, add organic and compostable materials to cover another 20% of the garden bed. Here are some options for this layer:
- straw
- fresh grass clippings
- fallen leaves
- mulch
- fresh organic matter (banana and orange peels, vegetable scraps, etc.)
You should have about 50% of your bed filled at this point. We recommend watering the top layer to help moisten the filling and allow the material to settle. Expect to see the level of layers diminish as time goes on, but watering the top before adding the soil helps you create more compact layers.
We paid $30 for one bale of hay that can cover 18 ft3 and for one 3.5 ft x 6.5 ft x 17-inch bed, we only needed a little over 3 ft3which is about $5 per bed.
Top layers: soil
The garden bed’s top layer is filled with high-quality soil (and compost if your raised bed potting mix doesn’t include this). We use a blend of FoxFarm Ocean Forest and FoxFarm Happy Frog potting mix, which contains a great blend of worm castings, fish emulsion, and aged forest compost.
For a budget-friendly alternative, you can also mix topsoil from your property with nutritious compost, worm castings, perlite, vermiculite, and other additives.
Spray the topsoil with more water to settle it into the bed and get planting! Once the plants are in their new homes, we like adding a mulch layer to keep the soil moist.
For one 3.5 ft x 6.5 ft x 17 inch bed, we spent $235 for a blend of Ocean Forest and Happy Frog that filled 32 ft3.
Tips
Here are more tips on how to spend less money filling a raised garden bed:
- Keep each layer moist by watering between each layer
- Try to use local resources to get free or cheap materials
- Local city and county recycling centers may offer free or discounted compost and mulch. Our municipal recycling centers offer this resource where you sign up for a pick-up time online, bring your own containers and shovels, and take as much as needed.
- Ask friends and family if they have organic materials they have. We picked up some old wooden logs from friends.
- See if you have any materials at home (we used our trimmings from the alder tree for filling).
- Find sales for raised bed potting mixes during the planting season. You’ll find nurseries and big box stores have sales during the spring.
- Search for hydroponics stores that sell bags of potting mix at a cheaper price. Our local hydroponics store sells Ocean Forest for nearly 50% off the price of nurseries and garden stores.
- ChipDrop is a company that offers free wood chip and log delivery to your home, with some caveats, including a minimum order of one truckload and limited variety options based on the arborists in your area. You can list varieties you absolutely do not want in the notes description. Note: We have not used this resource, so read their FAQs page to understand what to expect.
- Craigslist is a good place to find people offering free wood and mulch. Make sure to ask what variety of wood and if the wood has been treated in any way.