In this post, I’m going to share with you how to fill a raised bed cheaply.
I’ve also made a short (60 second!) video to answer the question…because if you’re anything like me then you have no time for waffle! I like things to be as simple as they can be.
Buying compost and topsoil can get expensive, especially if you have a few raised beds to fill.
This website is about making gardening accessible to all and a major part of that is demonstrating that you can grow your own on a budget.
Thankfully there are ways to make your money go further and fill a raised bed cheaply.
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Plants don’t actually need soil to grow. They need something that will anchor them to the ground and they need nutrients, water and air.
How they get these things varies between different methods of gardening.
Straw bale gardening is just one gardening method that utilises growing mediums other than soil) to grow vegetables.
The way we fill our raised beds for cheap makes full use of organic matter as it massively reduces the amount of topsoil we need AND overtime makes a lovely rich humus for our plants to grow.
We talk more about the perfect soil for growing vegetables in this post.
Let’s imagine for a minute that we’re filling our bed with soil. How much will we need to fill our bed?
To work this out we need a tape measure and simple formula (and a calculator!)…
Volume = Length x Width x Height
If you measure in feet then your answer will be in cubic feet. If you measure in meters then your answer will be in cubic meters.
So, let’s say your bed is:
your raised bed measures 2.4m (8ft) x 1.2m (4ft) and is 30cm (12inches) deep.
The calculation to find out the cubic meter is: 1.8 x 2.4 x 0.30 = 0.896m3.
If you were purchasing a bulk bag of top soil then you’d need to round the 0.896m3 up to 1 cubic meter (around a tonne in weight depending on if soil is damp and compacted or dry and loose.)
So, you could buy 1 cubic meter of good quality top soil and fill your raised bed for under £100.
However, if you have a few raised beds then it gets expensive…quickly.
I want to show how we filled our new raised bed for basically nothing.
Depending on your circumstances it may be possible for you to replicate this method and fill your raised bed for free.
If not for free then it will definitely save you money filling your raised bed with one of these methods.
This technique suits our style of gardening and hasn’t failed us yet. It is basically a way of making use of what we have around to fill our raised beds in the cheapest way possible.
I suppose you could say it’s a less organised version of Hugelkultur and Lasagne gardening.
1. First, we covered the ground with cardboard to suppress weeds.
2. Then add diverse layers of organic materials to the bottom of our raised bed:
This mixture of green (nitrogen) and brown (carbon) organic materials will breakdown overtime creating a fertile compost full of living organisms.
It’s important that the woodchip and food waste have begun decomposing before they are added to the bed if you are going to plant in your raised bed immediately.
3. Once half full, cover with top with soil (we collect ours from molehills in our field) and a layer of fine compost.
Compost from a compost bin would be ideal and free but we’re running low this year so used one bag of garden centre compost on top for £3.50 (our half rotted stuff went at the bottom of the bed).
The bed in the video is pretty shallow as we were using leftover materials to build a quick bed with a cover for tomatoes. If it was deeper then we would layer a few big logs in the bottom to retain and slowly release water.
Organic matter you can use to fill a raised bed cheaply:
A mix of both greens and browns is ideal because they will work together to speed up the composting process and create a home for helpful organisms.
Hugelkultur roughly translates as “mound hill” in German and involves building layers layers of compostable materials into a mound, covering them with soil and planting into it.
It’s like the method we use but a bit more structured.
It can be built as a mound or you can fill a raised bed in this way so it’s great if you’re lacking top soil and compost.
An added benefit is that the wood layer acts like a sponge so it stops the bed drying out.
As it all decomposes it provides plants with valuable nutrients and creates a rich compost.
Another option to fill a raised bed cheaply is to build a core. A core garden has a trench running through the middle that is designed to slowly release moisture and nutrients.
To make a core bed you need to…
1. Lay a cardboard base.
2. Add a layer of soil/ compost mix to your bed.
3. Down the centre of the bed lay a trench of wet organic matter that has already started decomposing e.g straw, grass clippings, twigs, leaves.
4. Pack your core down tightly so that it is around 15cm deep.
5. Water thoroughly.
6. Fill the rest of the bed with soil and compost mix.
Don’t worry if your bed has a mound along the core as it will.settle in time.
Keep your bed well mulched at all times to hold in moisture and suppress weeds.
There is no need to remake the centre trench year afrer year. Unless of course it dramatically reduces the need to water. Just make sure to add a layer of compost to the top of the soil every year.
If you have access to cheap or free decomposing hay then the Ruth Stout Method of building a bed will suit you.
1. Add a few inches of compost and topsoil to the bottom of your bed.
2. Fill with 25cm / 10 inches of decomposing hay
A great vegetable to grow with this method is the potato. Just add your seed potatoes after the initial layer of compost and cover with straw. They will help clear the ground and break it up nicely.
If you want to grow other crops then you’ll need to push back some of the hay to make a well shape and plant in some compost that you add to the well.
With the Return To Eden method you can fill a raised bed cheaply or for free depending on your resources.
It’s very similar to the Ruth Stout Method but uses wood chip rather than hay.
Wood chip can often be found free from a local tree surgeon l, gardener or farmer.
1. Cover the ground with cardboard and water it well.
2. Add a layer of manure if you have some.
3. Fill to roughly 15cm with a layer of compost and soil mix.
4. Fill to the top with woodchips.
5. To plant just move some woodchips aside and fill a ‘pot-sized’ hole with compost before planting.
You’ll notice that all of these 5 ways to fill raised beds cheaply share similarities.
They all make use of free or cheap organic materials to take the place of more expensive top soil.
Gardening on a budget is absolutely possible if you’re prepared to spend a little time sourcing useful materials.
A good place to start looking for freebies is your local swapshop sites and Freecycle. Making use of something that would otherwise go to waste feels great!
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