By Fiona Gallagher· permaculture designer · food, animals and preservation on 12 acres in Tassie
“After losing forty per cent of my heirloom tomato crop to damp, I learned that sealing seeds in airtight jars with silica gel is non-negotiable for our Tasmanian winters.”
Look, if you're off-grid in Australia, your seeds are your lifeline. Mess up storage and you're eating tinned beans for winter. No bullshit.
Moisture Content: The Silent Killer
Moisture & Temperature
Seeds must be bone-dry, because anything over 10% moisture sees them rot or sprout inside the bag, and Tasmanian humidity is a proper nightmare. Your packet should feel like a dry leaf in your hand; if it's soft or smells musty, bin it.
Fix it now: Spread seeds on a baking tray in a cool, dark spot for 2-3 days. Check every 12 hours. When they feel crisp, seal in airtight containers. No fancy gear needed.
Temperature: Keep It Cold, Not Hot
Room temp? Bad idea. Seeds last 3x longer at 5°C than 25°C. In Australia, that means no garage in summer. Your fridge is your best mate. If you're off-grid, a small fridge powered by solar is non-negotiable. No exceptions.
Longevity: How Long Do They Last?
It's not magic. Here's the real deal:
Tomatoes: 4-5 years (if stored right)
Beans: 2-3 years
Carrots: 1-2 years
Onions: 1 year (don't bother)
Test old seeds: Put 10 in a damp paper towel. If 70% sprout in 7 days? Keep them. Less? Toss. Wasting time on dead seeds is a rookie mistake.
Practical Tips (No Fluff)
Use glass jars with rubber seals. Plastic bags? They sweat. Bad.
Always add silica gel packs (from old electronics or $5 at Bunnings). One per jar.
Greenlife (NSW/QLD) - $3-$10 for standard seeds. Bunnings stock their basics. Cheap but reliable for basics like capsicums.
Australian Seed Bank (SA) - $10-$30 for bulk. Only if you're serious. They do 1kg bags of beans. Overkill for most, but good for big off-grid homesteads.
Don't waste cash on fancy "organic" seeds. They're the same as regular if stored right. Save your money for silica gel.
Bottom line: Dry, cold, and test often. Your garden depends on it. No excuses. Get it right or eat rice for the next 12 months.
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.
David The Good shows two low‑tech seed‑vault techniques you can set up with basic containers and a cool spot, giving you a practical way to keep seed viability high through multiple seasons.— Fiona Gallagher
