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Building an affordable raised garden bed can be easy with leftover housing materials, scrap timber and wood debris to save on soil.
The project
I had leftover Colorbond fencing from when our house was built and decided to make a raised garden bed using that and scrap wood.
One problem I had was, how do I fill a large bed with that much soil on a low budget? I couldn't dig it from the yard as we are on an inland island and it's all sand here.
I discovered Hugelkultur, which is an old German method of building up raised garden beds with logs, branches and organic matter and growing your produce in the soil above that. Then, as time goes by, the wood underneath eventually rots down and becomes nice organic matter for your garden bed.
This property backs onto a forest, so I used debris along my fence line, which ranged from very thick branches, to twigs and leaves.
Big logs first, then layers of branches, leaves and bark.
I stood on it to make sure it was compacted as much as I could, then gave it a good soak.
Horse manure is plentiful and cheap, so I did a layer of aged manure.
Big layer of soaked cardboard ripped into pieces and some more horse manure.
Layer of compost and cow manure.
Layer of soil, bought in bags from Bunnings.
Final bed after the external timber was stained, and strawberries planted along with a layer of pea straw.
After one year, I'd say the level has dropped down a full ridge in the Colorbond from the bottom layers decomposing. I harvested the strawberries and broccoli I had planted and dug down to the branches at the bottom of the garden bed to give the wood debris one big turnover. I was keen to see what the layers looked like after a year of watering, rain and having small crops growing on top. Pretty much everything other than the big logs and branches at the bottom had broken down. Smaller twigs crumbled in my hands and any leaves or cardboard in the upper layers were unrecognisable. Very happy with how it turned out and I imagine that it would take a few years for those big logs and branches to break down at the bottom.
I had no experience with this prior to my attempt. It's such a great concept for people wanting to dispose of garden waste and ideal for those on a budget as you only need to purchase and use enough soil on top for whatever you're planting.
How to build a raised garden bed
Grow your own garden in raised garden beds by following this step-by-step guide to building a raised garden bed by horticulturist and Workshop member Adam Woodhams.
For beginners, Adam has also shared a step-by-step guide to building a simple raised bed, while Mitchell shared how to build a raised garden bed using pallets.
When you are finished building your new raised garden bed, get expert advice from horticulturist Noelle on How to fill a raised garden bed.
Other raised garden bed projects
TheSaltyreefer used woody debris to fill these Hugelkultur raised garden beds in an affordable way and also nourish the soil.
Drainage grids were built close to the top of these raised garden beds by member mdstorrs so they don't need to be filled all the way with soil.
A raised garden bed can help improve the quality and quantity of home-grown fruit and vegetables. Find great ideas for your D.I.Y. raised garden bed in our Top 10 most popular raised garden beds.
Nice job, on a lighter note over time logs will turn into coal and then diamonds 
