By Mick O'Brien · carpenter & builder · sheds-to-homes, cabins and things that stay up in a storm

“After the 2019 bushfires blew my first three pine beds flat, I learned to anchor raised beds with 1.2m posts driven deep into the clay.”

Materials: What Actually Works (No Plastic Nonsense)

Forget fancy stuff. We're building for survival, not Instagram.

• Untreated pine (2x4s): $5.95 per 2.4m board at Bunnings. Do not use treated pine – it leaches arsenic into your food. End of story.
• Recycled timber: Raid your skip or ask neighbours for old fence posts. Free, and it's already been through the Aussie sun. Check for rot – if it crumbles, chuck it.
• Concrete blocks: $0.80 each at local builders' yards. Stack them 3 high for a 30cm bed. Don't use bricks – they leach lime and kill soil life.
• Avoid: Plastic sheets, landscape fabric, or anything that doesn't biodegrade. They'll be a plastic hell in 5 years.

Height: Why 30cm is the Sweet Spot

Too low? Weeds and pests win. Too high? Soil dries out faster than a dropped cup of tea in summer.

• 30cm (12 inches): Perfect for most Aussie soils. Easy to fill, easy to maintain. Don't go higher unless you've got a water tank and a spare 200L of water every day.
• 40cm (16 inches): Only if you're in a wet area (like the east coast). Otherwise, overkill.
• Under 20cm: Waste of time. You'll be knee-deep in weeds before you know it.

Soil Mix: The Only Mix You Need

Don't overcomplicate it. We're not growing orchids – we're growing food.

For a 1m x 1m bed (approx 0.3m deep):

• 1 x 20L bag topsoil ($5.95 at Bunnings)
• 1 x 10L bag compost ($12.95 at Bunnings)
• 0.5 x 20L bag horticultural sand ($5.95 at Bunnings)

Mix it in a wheelbarrow: Topsoil (50%) + Compost (30%) + Sand (20%). That's it. No fancy amendments. No "biochar" nonsense.

Australian Supplier Pricing (Bunnings, indicative prices)

• Untreated pine (2x4, 2.4m): $5.95
• Topsoil (20L bag): $5.95
• Compost (10L bag): $12.95
• Horticultural sand (20L bag): $5.95
• Concrete blocks (10-pack): $8.00

Final Word

Build it 30cm high. Use untreated pine or concrete blocks. Mix soil 50/30/20. Don't overthink it. Your garden isn't a hobby – it's survival. Get it done, then go grow some food.

When to Call a Professional

While many off-grid projects are achievable as DIY, certain situations require licensed professionals:

• Electrical work beyond basic 12V DC additions — requires a licensed electrician
• Structural modifications to buildings or load-bearing elements
• Gas line installation or modification
• Solar array installations above safe voltage thresholds
• Any work that affects the structural integrity of your property

Always check local regulations and obtain necessary permits before commencing work.