How to build a raised garden bed or retaining wall

Published 7:28am 26 March 2021

If you’ve been thinking about building a raised garden bed or retaining wall, the Easter long weekend is the perfect time to do it.

The experts at Nuway Landscape Supplies Pavers and Walls at Mango Hill have some tips and tricks to help you achieve the result you are looking for and avoid any costly mistakes.

General Manager Steve Myatt says, with good planning and weather, these two projects were manageable across a long weekend.

Pine sleepers have been a popular material in the past 12 months as residents looked for relatively inexpensive DIY gardening options during the COVID-19 shutdown.

Steve says sales increased 500 per cent as homeowners added vegetable gardens to their backyards.

“That happened across the board. We were almost at the stage of running out of timber in the industry,” he says.

Choose the right materials for the job

The best material depends on the level of DIY the homeowner is capable of.

Timber sleepers are quick and easy to work with, the next step up is blocks with ‘lips’ at the back to guide their assembly and then blocks that require more expertise to position.

Nuway has 27 varieties to choose from, ranging from $1.30 - $10 a block.

Steve says timber and blocks are perfect for raised garden beds because the soil does not heat up as much as other products and would not dry out as quickly.

This means the garden will not need to be watered as much, particularly in summer.

“Timber and blocks heat up on the outside, not the inside,” he says.

Careful planning is key before you get the shovels out.

“The first thing you need to do is some research on what you want as a finished product … what look you want,” he says.

He then recommends visiting a landscape supplier and getting some advice.

“We can help them work out what they need,” he says.

Most stock is available straight away, but if you have a big weekend project in mind it is best to order by Wednesday so it is there by Friday at the latest.

Products such as soil, sand and mulch can be ready for you within 4-5 hours, shorter for customers living nearby at North Lakes and Mango Hill.

Poor preparation will produce a sub-standard result, particularly with retaining walls.

“A lot of customers assume they can lay blocks straight on dirt, with no preparation,” he says.

Preparation is key

The ground needs to be level, so the blocks sit level and are not uneven at the top.

He recommends using road base, 250mm wide, 200mm deep and compacted. Then place 20mm of sand on top of it to help you level out the all-important first row.

Some people prefer a concrete footing, but it is not necessary in the majority of cases.

It is also important to make sure you have good drainage behind the wall.

“Most walls you see fall over don’t have the right drainage,” he says.

Another key consideration is block choice. Select the correct block for the job – the cheapest block might not be engineered for a high wall and will fall over.

If you’re unsure, get some advice.

“In general, customers ask how to do it. We spend time with them and go through it,” Steve says.

There are instructions available, and some great DIY videos on the Nuway website.

When it comes to raised garden beds, with the right products and advice, it is difficult to go wrong.

Again, you need to make sure the ground is level with crusher dust 100mm deep and the width of the block. You do not need a concrete base.

“It’s a good project because you can do it yourself and don’t have to pay someone to do it, saving you money,” he says.

“It’s also a project a family can work on together. It encourages kids to be active instead of being couped up inside.”