How to Fill Your Raised Garden Beds

There are plenty of questions floating around about how to fill raised garden beds and whether it’s possible to do it without spending a ton of money.

I totally get it. The idea of having to spend a lot, especially if you have several beds to fill, can feel overwhelming. But here’s the good news: it is possible to fill your raised beds on a budget.

Even better, the methods I’ll share with you aren’t just cost-effective; they’re also efficient for your garden, too. 

Sounds pretty perfect, right?

So, as you go through this article, you’ll know exactly how to fill your raised beds without breaking the bank, which materials to use, and which ones to avoid. 

If you're still figuring out raised bed sizes or looking for inspiration on raised bed ideas, those are things you can check out to make sure you're on the right track for a successful garden setup.

That way, you’ll be ready to start your garden with confidence (and a happy wallet!).

What Materials Should You Use

Before we get into the different ways to fill your raised beds, it’s a good idea to first know which materials you’ll be using. That way, you’ll have a solid foundation and be ready to get started.

Using Cost-Effective Materials

You can actually use a variety of cost-effective materials that not only save money but are also efficient for your garden.

Here is a list of great options to consider: 

1. Logs and Branches

Logs and larger branches break down slowly, providing nutrients to your soil over time. As they decompose, they can also hold moisture (like a sponge), especially during dry periods when plants need water.

You can simply place them at the bottom of your raised beds.

2. Cardboard

Cardboard is also a great material for preventing weeds from growing. It blocks sunlight, stopping weeds in their tracks while breaking down, making it a good option to consider. 

It reduces your workload by minimizing the need for weeding, and at the same time, it’s cost-effective since you can easily source cardboard in no time.

3. Newspaper

Just like cardboard, newspaper also serves as a natural barrier against weeds. As it breaks down over time, it enriches the soil with organic matter. 

Take note, though, that when using newspapers, you should avoid glossy pages, as they contain chemicals that can harm your plants and soil.

4. Organic Matter (Depleted Soil)

Do you have old potting soil or dirt from your previous garden?

If so, you can use it as an addition when filling your raised beds. It provides a nutrient-rich base to support plant growth without costing much.

Adding organic matter further enhances the soil by encouraging beneficial microbes. These microbes help break down nutrients, making them more accessible for your plants to absorb.

5. Straw and Hay

Straw and hay are excellent for retaining soil moisture, reducing the need for frequent watering. As they decompose, they improve soil structure by creating air pockets, which support root growth and enhance drainage.

However, if you’re using hay, ensure it’s at least a few years old to avoid introducing weed seeds.

6. Compost

If you have plenty of kitchen scraps or yard waste, why not turn them into compost? It’s a great way to save money on expensive materials and soil.

You might think it takes a lot of time, but the good news is that you can actually make compost in just 18 days using the Berkeley method.

7. Other Materials

Aside from the materials mentioned above, there are alternatives that you can actually use. Here are some of them:

• Shredded Paper
• Leaves
• Grass Clippings
• Wood Chips
• Coffee Grounds
• Eggshells
• Manure (well-aged)
• Pine Needles

What Materials to Avoid

Just a heads-up: When choosing materials for your raised beds, make sure they’ll actually support your plants' growth. 

While there are plenty of options out there, some materials may be treated with chemicals or substances that could harm your plants. So, it’s important to know what to avoid.

Here’s a list of materials to stay away from:

• Treated Wood
• Rocks or Gravel
• Soil contaminated with pesticides, herbicides or industrial waste
• Non-Composted Manure (to be safe,  use the well-aged manure)
• Plastic, Styrofoam, Synthetic Fabrics
• Treated Pallets
• Chemically Coated Wood Chips
• Metal scraps, Glass, or Construction Waste
• Overly Sandy or Clay Soil
• Weedy or Diseased Compost
• Excessive Synthetic Fertilizers

Always remember to avoid these materials when filling your raised beds so you won’t run into problems later on.

How to Fill Your Raised Bed

Now that you know what materials to use, it’s time to fill up your raised beds.

There are two common methods you can choose from, so you can pick the one that works best for you and whatever materials you can get your hands on. 

So let’s now  jump into the options.

The Hugelkultur Method

The Hugelkultur method is a practical way to fill your raised beds by using decomposing wood as the base. This method helps retain soil moisture and provides nutrients for your plants as the wood breaks down over time.

It’s actually simple, as long as you have the materials ready at hand.

Here’s how you can do it:

Step 1: Collect logs and branches

Start by collecting a mix of logs, branches, and twigs—the bigger, the better. These will form the base of your mound.

You don’t need to spend money buying logs or branches; you can simply use fallen trees, pruned branches, or any leftover wood from your yard work (if available).

Step 2: Build a mound

Next, if you have all the logs and branches at hand, place and arrange them into a mound shape, starting with the larger logs at the bottom and stacking smaller branches and twigs on top.

You want to create a nice, raised pile that will break down over time and feed your plants.

Step 3: Fill in the gaps

Once your mound is built, fill in any gaps between the logs with organic materials such as grass clippings, leaves, straw, or even kitchen scraps (like vegetable peels, fruit scraps, or coffee grounds). This helps create a rich, nutrient-dense layer as everything breaks down over time.

Step 4: Top with soil

Cover the entire mound with a thick layer of soil or compost. You want to make sure the wood is completely covered so it can begin breaking down underneath without drying out too quickly.

A well-applied, thick layer of soil on top will also provide an excellent starting point for your plants.

Step 5: Water the soil

Once everything is in place, give the mound a thorough watering to help settle it. This also kick-starts the decomposition process, allowing all the materials to work together to create rich, moisture-retaining soil for your plants.

Step 6: You can now plant into it

After a little while, once everything has settled and started breaking down, you can start planting directly into the soil on top of the mound. The decomposing wood will continue to provide nutrients and moisture, so your plants will be well-fed throughout the growing season.

It's a piece of cake, right? So if you want to adopt this method, feel free to do so.

Just remember that with the Hügelkultur method, it's important to layer your materials properly and give them time to break down.

How to Maintain Your Hugelkultur-Raised Bed Each Year

As you use your Hugelkultur-raised bed over time, you'll notice that the materials you initially added (especially the logs and branches) start to break down and decompose.

With that being said, the bed will naturally settle and lose some of its height. This is totally normal, but it means you will need to do some yearly fill maintenance to keep your bed at its best.

After your first growing season (or perhaps every year), take a look at the height of the bed. If you notice it has sunk, it’s time to top it off.

If the bed has settled about 3 inches, you’ll want to add around 3–4 inches of fresh material to bring it back up to its original height.

You can do this by adding new layers of organic matter (fresh logs, compost, straw, leaves, grass clippings, or even kitchen scraps work well for this purpose).

These materials will continue to break down and provide nutrients for your plants.

Once you’ve added your new layers, be sure to give the bed a good watering.

Over time, you’ll find that your Hugelkultur bed will need a little topping up each year, depending on how much it’s settled and how much the materials have decomposed.

But don't worry, it's an easy process that ensures your bed stays productive and continues what Hugelkultur does best.

Note: How often you need to do maintenance will depend on how much your Hugelkultur bed has settled and the materials you’ve used. In some cases, you might need to add more layers every season, while in other cases, a top-up every couple of years might be enough.

The Lasagna Gardening Method

The Lasagna Gardening method is a no-dig technique that’s great for filling raised beds with rich, healthy soil without disturbing the ground below.

It involves layering organic materials, which break down over time to create a nutrient-packed base for your plants.

Here’s how you can use the lasagna method to fill your raised beds:

Step 1: Prepare your base

Begin by placing a thick layer of cardboard or newspaper at the bottom of your raised bed. This serves as a weed barrier, blocking sunlight and preventing weeds from growing up through the bed.

Step 2: Add the first layer

Next, add a 2–3 inch thick layer of water-absorbent materials such as straw, dried grass clippings, or leaves. These materials help retain moisture, build the structure of your bed, and gradually break down to enrich the soil over time.

Step 3: Add the second layer

Now, it’s time to add a 4-8 inch layer of organic matter. You can use kitchen scraps (fruit and vegetable peels, coffee grounds), grass clippings, or compost. 

Be sure to alternate between “brown” materials (such as straw) and “green” materials (such as food scraps) to create a balanced mix that will decompose efficiently.

Step 4: Water each layer

As you build each layer, lightly water it to aid the decomposition process. This helps keep the materials in place and accelerates their breakdown, creating nutrient-rich soil more quickly.

Step 5: Repeat the layers

Continue layering these materials until your raised bed reaches the desired height, typically around 18–24 inches.

If you’re unsure about the ideal size for your raised beds, check out our guide on the best sizes for raised garden beds to find what works best for your space and needs.

Don’t worry about getting it perfect—just aim for a balanced mix of materials in each layer to support healthy decomposition and plant growth.

Step 6: Wait for decomposition

Once all your layers are in place, allow them to decompose over the winter (or for a few months, depending on when you start).

By spring, you’ll have loose, nutrient-rich soil that’s perfect for planting.

For more inspiration, check out our guide on the advantages of the lasagna gardening method to learn more about how this approach can transform your garden.

Common Mistakes When Filling Raised Beds

Filling raised beds can seem simple, but there are a few common mistakes people often make, and you'll want to avoid that for sure.

So just go through and read some of it so you'll take time to prevent this ahead.

One big mistake is not adding enough organic matter. You really want to include plenty of compost or other organic materials to make sure your soil is rich in nutrients.

Another mistake is overloading the bed with heavy materials, like big rocks or too much clay, which can mess with drainage and make the bed harder to work with.

You want a good mix of light materials that let the soil breathe and drain properly.

Also, be mindful of the height. If you fill your raised bed too high with materials that decompose slowly (like large logs), the bed can sink over time, leaving you with less growing space.

And lastly, people sometimes use treated wood or materials that may contain chemicals harmful to plants. It’s always best to go with untreated wood or organic materials that are safe for your garden.

Now that you've got those mistakes in mind, avoiding them will help you create a raised bed that’s healthy, productive, and easy to maintain.

Happy gardening!

Frequently Asked Questions (FAQs)