When we were budgeting out our first raised bed garden, I got serious sticker shock looking at the price of soil!
Filling even one bed with bagged soil adds up fast, and if you’re creating more than one, the cost can spiral out of control very quickly.
The good news is that raised beds don’t have to be filled completely with expensive soil.
You can layer in other ingredients at the bottom of your raised beds to add bulk, increase the fertility of your garden, and feed the worms and soil microbes that benefit your plants.
This method is similar to lasagna gardening and hugelkultur and works just as well in large containers.
(I also use a similar method for building in-ground garden beds called sheet mulching.)
This post shows you how to do it.
The Reason This Works
Organic materials like yard waste and kitchen scraps can be buried at the bottom of your raised beds before you add soil on top.
Over time, those materials break down into rich, organic matter that will support your plants from below.
Think of it like a slow compost pile working underneath your garden.
For the first season, this will help fill your garden beds right away so you won’t need to buy as much soil initially.
Plus it’s a great way to reuse yard and kitchen waste that would otherwise get thrown away.
Then you’ll add 8-10 inches of good soil at the top of your bed where you’ll be planting seeds and seedlings.
For Container Gardeners
In case you were wondering, layering works for containers, too!
Any pot or planter deep enough to allow 10 inches of soil on top has room for yard waste and kitchen scraps at the bottom.
It won’t break down as quickly without worms and other bugs to help, but it adds a bit of organic matter and fills the space.
TIP: Shred or cut materials into small pieces before stuffing them in the bottom of your containers.
What to Layer at the Bottom of Raised Beds
Don’t worry about layering precise ratios of browns and greens.
We’re not trying to make a hot compost pile; we’re just adding bulk to raised garden beds using materials that will break down over time.
Here’s what you can add to the bottom of raised garden beds.
Yard Waste
- Dead leaves (abundant in the fall!)
- Grass clippings (best used in small amounts and mixed with other materials)
- Small twigs and sticks (break big pieces into smaller ones)
- Wood chips (can be obtained free from local arborists)
- Non-invasive weeds that haven’t gone to seed (typically not an issue for deep beds)
- Old potting soil
- Dead houseplants (only if disease/pest free)
Kitchen Scraps
- Fruit and vegetable peels and trimmings
- Coffee grounds and paper filters
- Tea bags
- Eggshells
Paper and Cardboard
- Newspaper
- Shredded paper (uncoated; skip magazines and flyers)
- Plain cardboard (remove tape and staples first)
What NOT to Use
Skip anything that won’t break down cleanly or that will cause problems in the future.
Things like:
- Meat, fish, or dairy scraps (will attract pests)
- Diseased plants or soil
- Invasive plants, especially ones that spread by rhizome; mint, for example
- Treated or painted wood
- Glossy paper or coated cardboard
How to Layer Ingredients for Raised Beds
Layering is simple.
Start with the chunkiest ingredients and move to the finest ingredients.
Layer 1: Bulky Items
I put my bulkiest “dry” items at the bottom. Things like sunflower stalks, twigs, dead houseplants, etc.
Try to cut or break these large items into smaller pieces as best you can.
These take the longest to break down and it’s best to keep them out of the way of the plant roots growing in above.
I typically put weeds down here as well, especially if they are fresh. The deeper they get buried, the harder it is for them to find light and regrow.
Once you’ve got a couple inches of stuff in, get inside your raised bed and stomp the materials down as well as you can.
You don’t want big air pockets in there.
Plus, it’s fun!
If you can’t get into your raised bed, break down these larger materials before putting them in and use a shovel to help pack everything in.
Layer 2: Medium to Small Items
Next put in medium to small-sized items like shredded leaves, shredded paper, grass clippings, coffee grounds, and crushed eggshells.
Pack these materials down as well.
Continue adding layers of different ingredients into your raised beds.
Avoid piling a lot of one type of ingredient in any place.
Once you’ve filled your raised bed to your liking, hose everything down.
Moisture helps kickstart the decomposition process and also helps the layers to settle.
You may find room to add more!
TIP: Don’t forget that you can use cheaper topsoil as a layer as well. Just save your best (most nutrient-rich) soil for last.
Add Your Soil on Top
Once you’ve layered organic materials up to about 8-10 inches below the top of your bed, you can add your soil mix.
This is what your plants will actually be rooted in and growing in, so this is worth investing in.
A bagged raised bed mix is an easy-to-find option. Look for an organic mix for growing vegetables.
You can also mix your own with clean topsoil, peat or coco coir, compost, and sand!
After adding your soil, water the bed well.
If the soil settles too much, add more until the bed is as full as you want it.
What to Expect the First Season
Your layered materials will be slowly breaking down over the first season.
You may notice the bed settling as things decompose. That’s perfecly normal!
Plan to top off the beds with rich soil when the annuals have died back in late fall or the following spring before planting again.
Only working the top layer will keep microbes happy and preserve the texture of your soil which leads to happier plants (Learn why and more in my post on mistakes beginner gardeners make.)
You’ll find that your garden beds just get better and better over time.
For more tips on gardening in your first season, visit my page about starting a garden.
Your Turn to Grow
Filling raised beds doesn’t have to be costly.
This little trick of layering organic materials at the bottom of your bed will not only help keep costs down, but also enriches soil while reusing yard waste, kitchen scraps, and more.
Make the most of nature’s way of decomposing dead plant matter to bring life to new plants!
Happy gardening!