By Jenny Mills · rural nurse & homesteader · health, safety, law and the paperwork of going bush

“After losing three tomato crops to pH swings in my off-grid fertigation setup, I learned that testing water weekly is cheaper than replacing seedlings.”

Look, if you're off-grid in Australia and want to grow food without hauling water or manure, fertigation is the only way. No fancy tech, just straight-up working. Here's how to do it right.

Injector Types: Don't Waste Your Cash

Three types. Pick one. Stop overcomplicating it.

• Pressure-compensated injectors (e.g., Venturi): Cheap, reliable, no moving parts. $40-$80 from Hydroponics Australia. Works if your pump pressure is steady (most off-grid systems are). Best for small to medium gardens.
• Peristaltic pumps (e.g., dosing pumps): $150-$300. Good for precise dosing, but moving parts = more to break. Only get this if you're dosing multiple nutrients or have a big setup. Bunnings sells basic ones (like the Waterpik brand) but they're flimsy. Stick to Hydroponics Australia.
• Don't buy those "smart" injectors with apps. They're overpriced, break in the dust, and you're off-grid. Yo

  

  u don't need a phone to tell your plants to eat.

Dosing: Don't Overdose and Kill Your Garden

Too much nutrient = dead plants. Too little = sad lettuce. Simple math:

• Start with 1/4 strength of the bottle's instructions. Australian tap water is often hard (high calcium), so plants need less.
• Use a measuring jug (not a cup). 10ml per 100L water is standard for most organic fertilisers (like BioBizz or Green Sensation).
• Never mix dry fertiliser directly into the tank. It clumps and blocks your system. Dissolve it in a separate bucket first.

Example: For a 200L tank, use 20ml of liquid fertiliser. Mix it in a bucket with 2L water, then add to the tank. Stir. Done.

Reservoir Management: Keep It Clean, Keep It Going

Reservoirs get smelly, slimy, and full of algae if you don't manage them. Here's the fix:

• Size it right: 100L tank for 10-15m² garden. Too big = stagnant water. Too small = constant refilling. Hydroponics Australia sells 100L food-grade tanks for $65. Bunnings has cheaper plastic ones ($45) but they degrade in sun. Cover them.
• Weekly clean: Drain, scrub with vinegar (1:1 water/vinegar), rinse. No bleach. Kills beneficial microbes.
• Algae? Easy fix: Cover the tank with black plastic or put it in shade. If it's already green, add 1 tsp hydrogen peroxide per 10L water. Kills algae without hurting plants.

Australian Suppliers & Pricing (indicative prices)

Stick to these. No dodgy imports.

Final Word

Set up your fertigation system once, then forget it. Use a pressure-compensated injector, dose at 1/4 strength, clean the tank weekly, and buy from Hydroponics Australia. It'll cost you $150-$200 total. If you're doing it right, your veggies will grow faster, taste better, and you won't be hauling manure in the heat. Stop overthinking it. Do it.

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.