How to Fill a Raised Garden Bed
A simple, affordable soil recipe and what to put at the bottom of a deep bed.
By The Raised Bed Gardener Team · · 6 min read
Soil is the single most important ingredient in a raised bed. Good soil holds moisture without becoming soggy, drains freely and is rich in organic matter.
A simple starting mix
- About 60% quality topsoil or bagged raised-bed mix
- About 30–40% compost
- Optional: a little aged leaf mold, coir or peat for extra moisture retention
What about very deep beds?
If your bed is taller than 18 inches, you don't need to fill it all with premium soil. Many gardeners place untreated logs, branches or leaves in the bottom third. They break down slowly — expect the surface to settle and top up with compost each year.
Should I put cardboard underneath?
Laying plain brown cardboard over grass before filling helps smother it. Remove tape and glossy labels first.
Figure out how much you need
Use our soil calculator — or read how much soil a raised bed needs.
Beginner tip: Fill a little above the rim. New soil settles noticeably after the first few waterings.
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