As part of an approved plan which as to be followed our community garden needs to build a raised garden bed 3 metres wide x 15 metres long to 600 cm high.
What would be the best materials to use and the best construction method be?
Welcome to the Bunnings Workshop community @annj11. It's wonderful to have you join us and many thanks for your question about building a raised garden bed.
For a raised garden bed that size, especially at 600mm high, durability and structural strength are key. I would recommend using ACQ treated pine sleepers for the walls, paired with galvanised steel posts for the uprights. The steel posts will provide long-term strength and help prevent bowing over a 15 metre run, while the ACQ treatment is suitable for garden use and offers good longevity.
Given the length of the bed, make sure you include posts at regular spacings, typically no more than 1500mm apart.
The How to build a raised garden bed for privacy guide would be a great process to follow. It is built to 600mm high, just as you are intending, and the same construction method can easily be applied to a bed of any dimension. It steps through post installation, sleeper fixing and overall assembly in a clear way.
Please let me know if you have any questions.
Mitchell
