With home working on the increase and gardens becoming more of a focus in our lives its time to take you garden to the next level with raised planters. Raised planters are great for vegetables and flowers alike.
They add a good amount of structure to the garden with solid sides and can be built to fit in allotments or just down the side of your home. I have also seen some people convert a raised planter into a water feature.
This article will walk you through the easiest way to build you own sturdy raised planting bed. This DIY planting bed is cheap, easy and can give you a better result that you would get ordering one online!
The example here will build a 2 meter long by 1 meter wide by 0.4 meter deep wooden planter. Although you can use this same method for smaller or larger raised planting beds.
We will also include our recommendation for tools and materials.
- 120kg of hardcore or gravel
- 8 x 2m by 100mm by 50mm treated timber beams
- 8 x 1m by 100mm by 50mm treated timber beams
- 70 x 80mm screws
- 4 x 400mm x 75mm x 75mm treated wooden posts
- 850kg good quality top soil
- Wood stain/preserve
Almost all of these will be available from a good landscaping merchant. Delivery is usually cheaper than you would think too!
Watch this quick video demonstration to see what’s in store. Read the article for the details of each step.
Step 1: Dig out the base
The planter will be set on a flat and compacted base of hardcore (40mm Type 1 MOT if anyone asks) so before we can start building we need to dig out the base.
Start by marking out the footprint of the planter the go another 50mm beyond this to make sure you have plenty of room.
You don’t need to dig out the whole area so mark an inner edge 200mm in from the outer edge.
Next dig the level down to 50mm depth. Make sure the soil underneath is almost level and is compacted as much as you can get it with the pressure of your foot.
Step 2: Add a hardcore base
Hardcore is the same stuff that is used under roads, driveways and paving. It compacts into a solid and stable base which wont compress or subside once it has been compacted. This means your planter will stay level for years to come.
Pour in the hardcore evenly and spread it around until level. Use your spirit level to check that the whole base is level and up to the same height as the surface of the garden.
Compact using a tamping square or vibration plate.
Check the the level of the hardcore base again and move some around if it is not even.
Step 3: Build the bottom frame
Taking two of your 1m wooden rails and two of the 2m wooden rails lay them out on the hardcore base where they will be in the final product. Adjust until the inner angles are all at 90 degrees and it is a perfect rectangle.
With a single screw for each joint attach the wooden frame together.
Step 4: Add corner posts
Next its time to add the wooden posts.
Place these squarely in each corner and screw each rail to the post with 2 evenly spaced 80mm screws.
Make sure they are directly upright at 90 degrees using the spirit level.
The posts do not need to be in contact with the hardcore as they are primarily for support.
You can also cut the posts 30mm shorter than needed so they can be covered with soil on completion.
Step 5: Build the frame
Now that the structure is in place you can add the rest of the wooden rails. Using the alternating pattern shown in the picture, place and attach the next 3 layer of the raised planter framing using the 80mm screws.
Test and adjust throughout the process to make sure the angles of the planter are totally square.
Step 6: Add a liner
This stage is optional but advised. The soil will eventually rot the wood away, even if it is treated. To slow this down use brick liner or a pond liner and staple it to the inside of the wooden planter frame.
Make not to cover the bottom of the planter so that water can drain out into the ground below.
Step 7: Fill it with good soil
Using a wheelbarrow and a spade or shovel, add the soil to the planting bed. Add it in layers and lightly compact each layer with your foot. Avoid over compaction.
And that’s you ready to enjoy your new raised garden bed!
Where to build a raised bed
Raised beds are usually used for vegetable growing or for decorative gardening. When placing them make sure they are in a place which gets enough sunlight and is wind protected.
Type of wood to use
Planters should be built out of pressure or dip treated timber such as redwood, pine or larch. You can also build them out of hardwoods such as oak, beech, or hornbeam which will last longer but be significantly more expensive.
The best value woods are usually pressure treated softwoods available at many builders and timber merchants.
Type of soil to use
For vegetables and other plants to grow well they need free-draining soil with a good level of nutrients. Soil that is too sandy drains too quickly and doesn’t retain the nutrients, while compacted clay soil will hold the moisture rather than let it drain.
Both types of soil are unsuitable for growing vegetables or other plants. Clay soils also lack air pockets, which are important for reducing root diseases.
If you have sandy soil, the edges of the raised bed can be lined with clay material and if your garden is on a slope then build on an incline so there is good drainage away from your vegetable patch.
The best soils for growing vegetables are loamy soils that contain slightly more sand than clay. Loamy soil contains both airy and water holding components.
If you are working with existing soil that you know is not good enough, then work in plenty of compost or other organic matter such as peat moss/composted bark. Add lime if your soil tends to be acidic and add some extra fertilizer if it’s very lacking in nutrients (pH 6-7 is ideal).