Building A Raised Bed Garden – Cheap and Easy


Time For Planters and Raised Beds!

OK, so I’ve just started on my new range of planters and raised beds – yes, Spring is just around the corner here in ‘sunny’ Scotland. It doesn’t last long mind so we have to make the most of it!
One way however to get an early start, and indeed to prolong your growing season, is to use Raised Beds. A Raised Bed garden is able to be planted up earlier owing to the simple fact it is raised from the cold soil around it. It is free draining (if you have your mix right). And it is easier to protect against the elements.

example planters and beds

It also has a longer growing season for pretty much the same reasons. The soil around it will cool down faster than the Raised Bed, and be more prone to adverse weather conditions that will stop the growth of many veggies.

Raised bed are just an excellent way to add 2-3 extra months to the overall growing season – which means you are able to enjoy the fruits of your labors that bit longer.

Labors did I say? Yes indeed, there is always an element of work involved in gardening – however the good news is that once the beds are constructed, they are far less laborious to operate than the standard ‘row’ style garden. The infill is looser, there are fewer weeds, and the height makes them easier on the back – to mention just a few of the advantages!

Raised Bed Decisions:

When it comes down to it a Raised Bed can be built from many different materials – use what you have readily at your disposal is always a good start. For myself I have a good supply of reasonably cheap timber decking locally, so for this spring I am concentrating on building a number of different timber planters – as you can see from the pics on this blog!
So what’s the difference between a Planter and a Raised Bed? Simple really – Planters have a base on them and can usually be moved around. Raised Beds have no base (except perhaps in a shallow 4″ deep system) and are usually permanent fixtures.

Should You Treat A Raised Bed With Preservative?

container gardening book

This question only really applies to vegetable growers such as myself. It is question that often comes up, and often generates ‘more heat than light’ in discussions.

For myself I use pressure treated Tantalized timber – either decking or rough-sawn.
The biggest complaint about treated timber is that we may be poisoning ourselves by the chemicals leaking from the timber into the soil and from there into the food chain.

 Sounds reasonable enough. However of all the checks and investigating I have done, I can find no evidence that this is the case – at least not in the case of pressure treated timber. In fact all the evidence I have found says that the treatment does not leak out of the timber once it is treated.
This applies to pressure treated timbers.

As for other forms of brush or spray-on treatment. I would not use such applications on the interior of the timber as they will almost certainly leak into the infill material over time.

The only way for the chemicals to get back into the environment is by burning the timber and releasing it that way, or by putting shavings or sawdust into the compost heap – just don’t do it! Oh…and don’t light your barbeque with tantalized timber for obvious reasons!

However….I do understand that there are concerns in this department, and there is a simple solution if you are in any doubt. Use weather resistant untreated timber such as Larch, Douglas Fir, Cedar or even Oak.

Or simply line the interior of the beds with polythene membrane to prevent any possible cross-contamination.
To be honest even untreated pine will still give you 4-5 years of use, more if you use a decent thickness of timber over 2 inches (50mm).

raised bed gardening

Lining A Raised Bed Garden

Should the beds be lined with internal lining? Lining the interior of the Bed or Planter is especially important with untreated timbers as it will do 2 things.
Prevent the loss of water into the timber (dry timber can soak up your water like a sponge)
Protect the timber against rot as the interior of the bed will be by its nature continually damp.

In the case of treated timber a lining will..
Help prevent the loss of water (not quite as big an issue owing to the treatment process)
Protect against possible chemical leakage (again depending on your position/view)
Bottom line is that whilst lining is not absolutely necessary, it will generally be advantageous to your overall efforts.

Building A Raised Bed

For these examples, use decking with decking screws for the fixings and you’re ‘good to go’. I won’t go into some lengthy lesson here on fixing them together – rather I will leave it up to the pics to speak for themselves 🙂

square foot raised bed

So we get down to the actual construction, which is really simplicity itself – whether you use untreated or treated timber. As for building the raised bed itself, the general rule is not to waste money by leaving silly offcuts you cannot use for something else!
On the examples peppered throughout this post I have used 30mm x 145mm tantalized timber decking.

This timber is extremely robust and will last for a minimum of 10 years and more likely 15 years from my experience.
In the UK we are all decimalized now so timber tends to come in 2.4 or 4.8 metre lengths. This means that it is best to think in subdivisions of these lengths wherever possible to prevent wastage.
For instance a 4 x 4 Raised Bed is actually 1200 x 1200. Construction is simplicity itself.

This is a size commonly used in Square Foot Gardening methods.
Cut 2 lengths 1200 long, 2 lengths 1140 long. And 4 posts 50 x 145 or 350 long (if you wish to use them as anchors at the corners).

example of raised bed

For the Long Raised Bed..
4 lengths at 2 mtrs (cut from 4.8 mtr lengths). 4 lengths at 800mm. 4 corner posts at 50mm x 290 (longer if you wish to use as corner anchors). 2 centre post for added strength.
Planters take a little longer to construct because they have a base attached. Simple tip. Take 2 planks of decking the appropriate length. Cut 2 lengths of 2×2 or similar for feet at 290 long. Fix to the underside planks, (leave a 10mm gap for drainage) with decking screws to form the base.
For the sides.

Build 2 sides with 2×2 corner posts attached, then affix each side to the base with screws/nails along the edge, before fixing the ends of the planter.

Drill holes in the base for drainage, otherwise your planter will become waterlogged in no time.
Line or not according to your preference, and you are ready for infilling and planting!

decking garden planters

Please feel free to check out my other posts on container gardening and small space gardening, whether you are using Raised Beds or any other form of ‘container’ to grow your veggies.

RAISED BED BUNDLE

As for any concerns you may have regarding treated timber products for constructing your Raised Beds, I would encourage you to check out the links below that will give an explanation from the experts on the chemicals used for treating exterior timbers.

Tanalized Timber references to check out..

Wiki Page on wood preservation.

Specialised site on Tanalised Timber products

James

Best Selling author of several no-dig gardening books, James has over 40 years of gardening knowledge and experience to share with like-minded gardening enthusiasts.

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