Save money with a DIY garden box. When you make your own raised garden bed, you can make it exactly the right dimensions to fit your space. This is how we made ours.
There are lots of benefits to growing your own vegetables at home.
One of the best ways to grow vegetables is in a raised garden bed!
But don’t spend a fortune on fancy garden boxes from the hardware store. Make one yourself and save.
Below you will find the instructions for making a simple raised garden bed – a great weekend DIY project.
Why build a garden box? The benefits of a raised garden bed
Why bother building a garden box when you can just plant directly into the ground?
A raised garden has some benefits over a traditional garden bed. They include:
- Easy access to plants and therefore easier on your back.
- Good drainage if you use good soil and plenty of organic matter
- The soil is above ground and therefore warms up quicker than ground soil, especially if you use plenty of compost.
- The raised bed can give better drainage.
- There is less maintenance of a raised bed, especially if you use a no-dig method of gardening.
- Raised beds look nice with clearly defined borders
- If you live in an area with contaminated soils (city soil can have high levels of lead, for instance), a raised bed will allow you to still garden in uncontaminated soil.
- Garden boxes are mobile. This is especially good if you’re a renter and want to take your garden with you.
Which wood should you use for your DIY garden box?
There are several choices when it comes to choosing what to build your raised bed with. These include:
- Hardwood sleepers
- untreated fence palings (pine or hardwood)
- treated fence palings
- hardwood decking
- composite decking
Hardwood sleepers can be a great choice if you can source salvaged ones. Otherwise, they can be expensive and it’s probably cheaper to just buy a raised bed from the hardware store.
Treated fence palings are cheap to buy, don’t rot very quickly and are easy to use.
However, any CCA treated palings are treated with copper, chrome and arsenic. This is problematic due to the concern that arsenic can leach into the soil and therefore the food that you’re growing.
To avoid this problem, you can opt to use untreated wood. Just be aware that untreated wood will rot quicker (it should still last several years) and can be susceptible to termites. For a more durable option, use hardwood.
If you can find it, salvaged untreated wood can be an economical as well as ecological choice.
Another alternative is to use ACQ treated wood. The ACQ stands for Alkaline copper quaternary. As it doesn’t have arsenic in it, it is safer to use. These palings are harder to source and you may need to visit a lumberyard.
(You can find out what all the treatment terms are here.)
A third alternative is to line the sides of your garden bed with plastic or paint the surfaces with an oil-based polyurethane product or paint. Don’t line the base with plastic – you want good drainage at the bottom. This recommendation comes from the New South Wales Environmental Protection Authority.
We chose not to worry about using treated wood. According to some sources, uptake of arsenic by plants is minimal, especially in above-ground food crops and compared to other sources. Obviously, you choose the materials that are right for you.
The final option is composite decking, which is made from a combination of bamboo or other fibres and recycled plastic bottles, making it a great eco choice. Composite wood is sealed, so no leaching toxins into the soil. It handles similar to hardwood, so no special tools required and it lasts many years. It is more expensive than treated pine, however.
Where should you put your garden box?
If you’re growing vegetables in your garden box, then they will need plenty of sunlight to grow well. So keep this in mind when planning where to put your raised bed.
If you live in a hot climate, your garden will benefit from some shade. In a cold climate, it will benefit from being next to a heat source, like a brick wall that gets sunlight.
One benefit of a raised garden is that you can cover it more easily than an open garden. In a cold climate, you can cover it with a cold-frame to keep the frost off and extend the growing season. In a very hot climate, cover it with shade cloth during the hottest months.
Can you build a raised garden directly on top of grass and concrete?
It’s possible to put your DIY garden box directly on the lawn without cutting out the turf. To stop the lawn and weeds growing up, place a thick layer of newspaper and/or cardboard over the grass inside your garden box.
You can also place a raised garden bed directly on concrete and pavers. To reduce staining, you can use a raised bed liner, cardboard or put a thick layer of gravel or stones at the bottom of the garden box to increase drainage.
Avoid overwatering and waterlogging your garden to prevent run-off staining the concrete.
How deep should your raised bed be?
The depth of your garden box depends on what you want to grow. Root vegetables like carrots will need a deeper box than if you’re just growing herbs.
With this in mind, your garden box should be at least 30cm deep.
If your raised garden is on good soil, then this depth might be sufficient. However, if it is placed on concrete, lawn or poor, compacted soil, you will need a deeper raised garden – between 40cm and 90cm deep depending on what you want to grow.
The instructions below are for a 40cm deep garden.
Filling Your Garden With Soil
If your garden box is deep or you are filling several, you may need to buy a load of topsoil from a landscaper to fill it or you can try to get soil for free.
Don’t skimp and get poor quality soil – good soil is so important for growing good plants.
Along with quality topsoil, you will want to enrich the soil with compost and manure and then cover it with mulch to keep in the water.
The no-dig gardening method is perfect for a raised garden bed. It saves time and labour, builds the soil (tilling breaks down soil structure), reduces watering, there are fewer weeds and in some cases, higher yields.
Raised Garden Bed Plan
Below are the instructions for making a DIY garden box similar to the one we built.
Our garden is divided into two boxes, the middle support makes it more stable, but if you want one long garden, leave the middle cross-section out.
I’ve given sizes, but you can adjust the measurements and make your garden bed any size you like.
- 14 x 1.5m plain wooden fence palings (preferably untreated or ACA treated)
- 2-3 1500mm hardwood garden stakes
- Box of screws
- Face mask
- Safety glasses
- Hand or electric saw
1. Cut your palings and stakes to size
- Wearing a mask and safety glasses, cut 6 of the fence palings in half for the short ends and the middle supports.
- Trim off the sharp end of the garden stakes and cut the stakes into 400mm lengths.
2. Construct the long sides
- To make the long sides of the box, lay two cut stakes on the ground 1.5 metres apart (the length of the fence pailings). Place another stake in the middle.
- Line up the fence palings on top of the stakes. Drill holes and screw securely into the stakes.
- Repeat this process for the other side of the box.
3. Construct the short sides to complete your raised garden
- Screw four of the shorter palings to the middle stake uprights for the box divider (this is optional but it makes the box more sturdy).
- Screw the remaining short palings to each end of the box to complete.
- You now have a sturdy raised garden bed that's deep enough to grow root crops
It's important to wear a mask and not breathe in sawdust, especially when working with treated wood. Clear up all sawdust once wood is cut to avoid breathing it in.