9 Ways to Fill Raised Bed Gardens Cheaply

by Bethany Hayes

Filling raised garden beds can be expensive, and if you’re gardening on a budget, you might wonder how you can fill raised beds cheaply. Even if you have the money, no one wants to spend tons of money on dirt!

Two years ago, I filled a few garden beds with bagged soil and spent over $50 per garden bed. If you have four or more beds, this adds up fast! I decided that I never wanted to spend that again, and I looked for ways last year to fill the garden beds cheaper.

It turns out there are several ways to bulk up your garden soil without spending more money. Don’t let your wallet empty as you fill up your raised beds; here are some of my best tips and what you need to know about the soil you need for raised beds. 

Garden Soil vs. Raised Bed Soil 

When you build raised garden beds, you might assume that you can take garden soil and fill the beds, but that’s not true. You want to use suitable soil for your beds to provide your plants with the right amount of nutrients and water drainage to avoid standing water. 

Let’s take a look at some of the differences between garden soil and raised bed soil. 

The Breakdown of Organic Material 

One of the major differences is that garden soil breaks down humus and organic materials faster than you can restore it unless the roots are planted so deeply that the roots can access nutrients further into the ground. 

All plants need nutrients, and humus is necessary. The more humus in the garden soil, the better it is for your plants and veggies. You want the nutrients to be available for your plants all growing season long; that’s not so easy in garden soil. 

Garden Soil Holds More Water 

Water is needed for plants to grow, and moisture in the soil is a major part of root development. However, when water doesn’t have proper drainage, it causes 

Garden Soil Can Be Salty

Another difference is that garden soil can contain higher amounts of salt than raised bed soil. Salt is highly corrosive; it even damages sidewalks and driveways if left in place! Most plants cannot grow in soil that contains too much salt. 

9 Ways to Fill Raised Beds Cheaply

The first time I filled raised beds with bags of dirt from Walmart, I decided there was NO way I could afford to fill as many garden beds as I wanted to have. Filling one raised bed is pricey, but not a big deal, but my garden has many beds. I had to find a way to fill raised beds cheaply.

Lucky for everyone, there are ways to fill garden beds cheaply without needing to drain your savings account. Here are some of the best tricks that work and won’t cause your garden to flop. 

Hugelkultur Gardening

Never heard of hugelkultur gardening? Don’t let the name fool you; this is a simple gardening method that works and results in large harvests. 

The main idea behind hugelkultur gardening is to bury as much rotting debris beneath the soil. It could be sticks, food scraps, grass clippings, wood chips, shredded leaves, and other materials. You also want to add logs that will break down over time; it’s essential to have large pieces for hugelkultur.

If you use this method, the bed needs to be filled 10-12 inches deep, filling all of the gaps with rotting materials and soil. 

Use Lasagna Gardening

Lasagna gardening is similar in theory to hugelkultur gardening, but you have to consider the layers you create. At the bottom of the raised bed, you add a layer of cardboard to smother the grass and kill off any weeds. It also stops weeds from growing up later. 

After the cardboard, you add a layer of leaves and more cardboard. Continue to create layers with different organic materials and soil. You’re essentially creating a compost bin inside your garden bed because everything breaks down gradually. 

Try Core Gardening 

Most people have never heard of core gardening. When you first read about it, you might think that it’s too complicated, and there is no way it could work for you, but you’d be wrong. Core gardening creates a “sponge” in the center of your garden to hold water, wicking it two feet in both directions. 

Core gardening drastically reduces how much you need to water, but most gardeners say you’ll have drastically fewer weeds. 

Create dig in your garden bed that is ten inches deep and in the center of your raised bed. Layer down a few layers of cardboard, and fill the core with straw bales, leaves, grass clippings, or old twigs. You can use one of these materials or mix them. 

Fill the rest of the core in with a mixture of topsoil, compost, and potting soil. This trench will look like a mound in the middle of your garden, and it needs to be watered thoroughly so that it has moisture to give to your plants throughout the gardening season. 

Use Ruth Stout Gardening 

Ruth Stout’s gardening is similar to Back-to-Eden gardening. The idea behind this type of gardening is that you cover all of the exposed soil with organic mulch that will eventually decompose into the ground, adding nutrients. Keeping soil covered comes with several benefits, like reducing erosion and suppressing weed growth. 

When you use Ruth Stout gardening, you cover all of your garden with a thick layer of hay. You put all of your plants into your garden with the hay surrounding them. Other methods use wood chips or compost, and for these methods to be effective, you have to make sure the layers are four to six inches deep.

Using this method helps to fill your raised bed quickly! 

Add Peat Moss 

If you go to any garden store, you’ll find large bags of sphagnum peat moss. Peat moss is acidic, so you have to be careful not to add too much to your soil unless you’re growing acid-loving plants like peppers, azaleas, or sweet potatoes. 

However, adding peat moss to your soil is a great way to bulk it up without buying extra bags of potting soil or topsoil. 

Homemade Compost

I can’t think of anything better to add to your garden than homemade compost, and compost is free if you make it at home. Bagged compost is expensive; it’s like gold for your garden, but making it at home requires only time and scraps from around your home.

If you want to use compost to fill raised beds cheaply, you need to get started on your compost pile the year before building the beds. Compost takes six to 12 months to develop, so you have to plan. You’ll add all kinds of ingredients like grass clippings, kitchen scraps, newspaper, shredded leaves, and more. 

Add Composted Manure 

Have you got chickens or other farm animals? Turn their waste into composted manure for your garden. 

You must always avoid adding fresh animal manure to your garden. Manure contains high amounts of nitrogen, and if you plant in it too quickly, it’ll burn your plants, killing them. The best manure comes from chickens, cows, horses, sheep, rabbits, and goats. Never use manure from dogs, cats, or humans because of the bacteria inside of the waste. 

Ideally, you’ll compost the manure for at least a year, so it takes time to plan. However, since animals create a never-ending amount of waste, it’s the perfect way to fill raised beds cheaply. Let the animals save you some money, finally. 

Buy Soil in Bulk 

I gave up buying bagged soil years ago. When you need to fill a few garden beds and each bag is over $3, sometimes closer to $5, it adds up too quickly. 

That’s where buying soil in bulk comes into play. Many gardening stores and local nurseries offer big discounts if you buy soil by the truckload or yard. It’s a much more affordable option than individual bags. 

Add Materials for Aeration 

No matter which one of the above tips you use for filling raised beds cheaply, you still need to add materials to your garden beds that encourage good aeration. Aeration allows for proper airflow throughout the soil, allowing water to reach the roots and avoiding compacted soil. 

You don’t want to add too many aeration materials because it’ll cause the soil not to hold water. Try materials like perlite, pumice, lava rock, or coarse sand. 

How Much Soil Do You Need to a Fill a Raised Bed?

After you decide how to fill raised beds cheaply, you have to figure out how much soil you need to fill your raised beds. The first step is to take the measurements of your bed, which you’ll know if you built or bought them. You have to multiple each measurement to get the cubic feet of soil to fill the raised beds. 

For example, if your garden bed measures 8’ x 4’ x 1’, you need 32 cubic feet of soil to fill the bed. You should buy a bit extra because the soil tends to settle, and you might end up with gaps. 

FAQ About Filling Raised Garden Beds

Do you have other questions about filling your raised garden beds? Here are a few of the most common concerns that gardeners had when building and filling raised beds. 

Do I Need to Remove Weeds at the Bottom of Raised Beds?

No, you don’t have to remove weeds at the bottom of the raised bed, but not eliminating weeds makes it possible for the weeds to grow up still and invade your new bed. 

One of the best practices is simply covering the bottom of your new raised bed with cardboard, suppressing the weeds. Cardboard decomposes over time, but by the time that it does, the weeds will be dead. 

Is Topsoil OK for Raised Beds? 

Topsoil belongs as part of the soil mixture used in raised beds, but you cannot only use topsoil to fill your new garden bed. Topsoil is a filler; it bulks up the amount of soil you have in your garden bed. However, plants need plenty of nutrients, and topsoil doesn’t contain enough organic matter for your plants to grow as needed. 

Typically, when you create a raised bed mixture, topsoil should account for 10-20% of your mixture. You don’t want to increase it beyond that because your plants need plenty of nutrients. 

Can You Fill a Raised Bed with Just Compost?

No, you should never fill a raised bed with only compost. It should account for 30-50% of your garden soil when creating a soil blend for your raised beds. While compost will give your plants plenty of nutrients, the soil will drain away too quickly, washing away the nutrients, causing your plants to starve. 

Final Thoughts

Filling raised beds is an expensive endeavor, which makes many people shy away from gardening. Don’t let the cost prevent you from gardening; try a few of these tips for filling raised beds cheaply. Your plants and budget will be happy.