How to make a soil factory
How to Make a Soil Factory: Turn Food Scraps into Soil (Even Without a Garden)
If you've been bokashi composting your food scraps but don't have garden space to bury them; or you've got a traditional compost bin that's smelly, pest-prone, or needs constant turning — there's a simple fix that's been gaining traction online: the soil factory.
A soil factory is nothing more than a sealed storage container where you combine old soil or bagged soil with finished bokashi scraps, let it sit for a few weeks, and end up with rich, nutrient-dense soil you can use for growing food, potting plants, or even feeding worms.
No garden or backyard is required. This type off soil factory works on a balcony, in a garage, or in a small apartment.
What You'll Need
- A large heavy duty plastic storage container with a tight-fitting lid (a 55–57 litre tote works well).
- Either a bag of soil or old/used potting mix / soil (enough to fill the container about halfway, plus a bit extra)
- A batch of fully fermented (pickled) bokashi food scraps
- A spray bottle of water
Why a Soil Factory Works So Well
No turning required. As long as you mix the bokashi scraps into the soil thoroughly at the start, that's it. If it's not, you may need to mix it again in a week or so - but apart from that, there shouldn't be any ongoing maintenance. This is a big departure from a traditional cold compost pile, which needs regular turning to aerate and break down properly.
No odour, no pests. Fermented bokashi can smell pretty strong, and that smell tends to linger if it's dug into an open garden bed or left in an outdoor bin. Sealed inside a storage container, the smell stays fully contained — and so do the pests it might otherwise attract. That's what makes this method suitable for small or shared spaces like balconies, patios, and garages.
Worm-friendly. If you run a worm farm, you may already know worms don't love raw bokashi — it's too acidic for them straight out of the bucket. Processing it through a soil factory first neutralises that acidity within a week or two, so the resulting soil is much easier for worms to digest.
You get out roughly what you put in. This is one of the biggest advantages over a traditional cold compost pile. Often in cold compost system at home, a large portion of your organic matter — often 50% or more — is lost as CO2 during breakdown, and the pile also compacts down significantly as it decomposes. In a sealed soil factory, because the bokashi has already been fermented rather than aerobically broken down, very little organic matter escapes as gas. In practice, you're growing your soil: whatever volume you put in is roughly the volume you get back out. So if you're reconditioning old garden or potting mix soil — say 30 litres — and mix in 10 litres of finished bokashi scraps, you'll end up with roughly 40 litres of usable soil.
It's fast. A traditional compost bin can take anywhere from six months to a year or more before the matured compost is ready to harvest. A soil factory with pre-composted food scraps (aka Bokashi), by contrast, produces usable soil in a matter of weeks — a fraction of the time.
Step-by-Step: Building Your Soil Factory
- Add your base layer of soil. Take a large storage container (around 55–57 litres) and scoop in old potting mix or used soil until it's about half full.
- Add the finished bokashi. Empty your fermented food scraps (roughly a 10 litre bucket's worth) into the container and mix thoroughly with the soil. Good mixing at this stage is what allows you to skip turning later.
- Top it off. Add another layer of soil on top — about 5-10 litres — to keep everything well insulated.
- Keep it moist. If that top layer of soil is looking dry, give it a light spray of water. This helps the bokashi continue to break down properly.
- Seal and wait. Clip the lid on tightly and leave the container undisturbed for at least 2–3 weeks (allow 4–8 weeks in colder months, since the breakdown process slows down in lower temperatures).
- Check for readiness. At around the 3-week mark, there should be no fermented smell left at all — just an earthy soil scent. That's your sign it's ready to use for growing plants or food, or to feed to your worm farm.
Small Space? No Problem
One of the best things about this method is that it doesn't require any actual ground. Even if you're working entirely on concrete — a balcony, a courtyard, a garage floor — a sturdy storage tote is all you need. It's portable, pest-proof, and easy to set up anywhere.
Quick Recap
| Step | Action |
|---|---|
| 1 | Half-fill a storage tote with old soil |
| 2 | Mix in finished bokashi scraps |
| 3 | Add a top layer of soil for insulation |
| 4 | Spray with water if dry |
| 5 | Seal the lid and wait 2–6 weeks |
| 6 | Use once the smell turns earthy, not fermented |
Whether you're an apartment dweller without a scrap of garden, or a gardener who's run out of room to bury bokashi, the soil factory method turns a sealed plastic tote into a low-effort, low-odour way to create genuinely good soil — no turning, no smell and no pests.