Why potatoes and onions need vented bulk bins

Key takeaways

Potatoes and onions keep respiring after harvest — giving off heat, moisture and CO₂. Vented bulk bins let that air move through the whole stack so the crop dries down, cools and stores for months instead of sweating and rotting in the middle of a sealed box.
The FAO estimates roughly 14% of the world’s food is lost between harvest and retail — and post-harvest storage is one of the cheapest levers a grower controls.
Match the bin to the crop and the shed: 1165 × 1165 mm is the common Australian footprint, with real vented volumes running from a ~470 L half bin to a ~1,400 L bulk box.
Food-grade HDPE and PP hot-wash clean between loads, won’t splinter or harbour pathogens like timber, and survive many seasons outdoors.
Store potatoes and onions separately — onions give off ethylene and want dry air, potatoes want cool and humid; the same vented bin suits both, but not in the same room.

Potatoes and onions keep living after harvest — respiring, giving off heat, moisture and carbon dioxide. Vented bulk bins let that airflow move through the whole stack, so the crop sheds field heat, stays dry and stores for months. Solid-walled bins trap exactly what spoils it. This guide covers why airflow matters, what poor storage costs, how much crop each bin size holds, and how to choose for your shed.

Why do potatoes and onions need vented bins?

Because both crops are still alive in the bin. Freshly lifted potatoes and onions respire — burning sugars and releasing heat, water vapour and carbon dioxide — for the entire time they are stored. Vented walls and an open base let air move through the full column so that heat and moisture escape, instead of pooling in the middle of the stack where rot, sprouting and skin breakdown begin.

Pack a freshly lifted crop into a sealed box and you concentrate exactly the conditions that spoil it. A solid wall stops the stack from breathing, so the centre of the load sweats, warms and softens while the outside looks fine. Genuinely vented bins — slots through the walls and an open base, not a couple of token holes — keep the whole column dry and even in temperature, which is the single biggest thing a grower controls between harvest and pack-out.

The benefit compounds in a stack. When vented bins column-stack with their openings aligned, the walls and open bases form continuous vertical channels through the whole block of crop. In a forced-air or pressure-cooled store that lets the fans pull conditioned air through every bin at once rather than just past the outside of the pallet, so field heat comes out of the deep centre of the stack instead of lingering for days. Drop a solid-walled box into that same stack and it blocks the channel, forcing air around the load and leaving a warm pocket — which is why mixing vented and solid bins in one cool-room cools unevenly.

Curing happens in the bin too

Onions in particular need to cure before long storage — drying the necks and outer skins down so they seal against disease. That needs warm, moving, low-humidity air around every bulb, which a breathable bin delivers in place. Potatoes go through a shorter wound-healing (suberisation) period after lifting that also wants gentle airflow and a steady temperature. In both cases, a bin that traps moisture holds precisely the dampness that rots a neck or seeds a soft patch. For the onion-specific detail, see our guide on curing and storing onions.

How much does poor storage really cost?

More than most growers count, because the loss is spread across the whole season rather than landing in one invoice. The Food and Agriculture Organization of the UN estimates that around 14% of the world’s food is lost between harvest and retail, with poor handling and storage a major contributor (FAO, The State of Food and Agriculture 2019 — fao.org). For a respiring crop sitting in store for months, breathable handling gear is one of the cheapest levers available to move that number.

Australia takes that waste seriously enough to set a national target. The Australian Government, working with industry through the National Food Waste Strategy, has committed to halving food waste by 2030 (Department of Agriculture, Fisheries and Forestry — agriculture.gov.au). On-farm and packhouse storage is squarely inside that goal: every bin of crop that ships instead of spoiling is product sold and waste avoided.

The mechanism is simple. Shrink (moisture loss), rot and premature sprouting all accelerate when heat and humidity build up in a stack. Move the air through the load and you slow all three at once — extending the window in which the crop is saleable and cutting the percentage that never leaves the shed.

How much crop fits in a vented bulk bin?

A bin’s litre rating is not its weight rating — how many kilograms it holds depends on the crop’s bulk density. Bulk potato packs at roughly 650 kg per cubic metre and onions at about 550 kg/m³ (whole onions leave more void space), so the same bin holds noticeably more potato than onion. Multiply the volume in cubic metres by the density to get the weight: a 700 L bin is 0.7 m³, and at 650 kg/m³ that’s about 455 kg of potato.

The table below converts three real Australian vented bin volumes into approximate fill weights for the two crops. Treat these as planning figures for sizing a fleet — variety, size grade, moisture and how the bin is filled all move the real number.

Vented bin (footprint)	Volume	Potato fill (≈650 kg/m³)	Onion fill (≈550 kg/m³)
Low half bin (1162 × 1162 mm)	≈ 470 L	≈ 305 kg	≈ 260 kg
Full bulk bin (1120 × 1120 mm)	≈ 700 L	≈ 455 kg	≈ 385 kg
Giant pallet box (1300 × 1150 mm)	≈ 1,400 L	≈ 910 kg	≈ 770 kg

Fewer, larger bins mean fewer lifts per tonne and a tidier stack, but a near-tonne box has to be load-rated to carry the bins stacked on top of it — always check the static (stacking) rating against your store’s stack height. For the full crop-by-crop conversion across more bin sizes, see our produce bin sizing chart.

For high-volume potato storage, a single giant vented box carries close to a tonne of crop on a stable 4-way base — moulded in one piece so there are no joints to trap dirt or fail under load. It breathes through both the walls and the floor, which is what keeps the deep centre of a near-tonne load from sweating.

What makes a produce bin food-grade?

It comes down to the polymer and the surface. Food-grade vented bins are moulded from HDPE or PP — materials safe for direct food contact: non-toxic, non-tainting, non-absorbent and cleanable. In Australia and New Zealand, food-contact materials sit under the food standards framework (Food Standards Australia New Zealand — foodstandards.gov.au). In practice that means a smooth, sealed surface that sanitises clean — not raw timber that soaks up moisture and can splinter into product.

Smooth, radiused mouldings with no open grain or crevices for bacteria and soil to sit in.
Hot-wash and sanitise friendly — quality HDPE and PP take a wash-down between crops without degrading, so the same bin runs clean season after season.
No foreign-body risk — no nails, staples or splinters to end up in graded product, which matters for any HACCP-aligned line.
Won’t rot or harbour pathogens — unlike timber field bins that absorb moisture and carry disease between seasons.

HDPE stays tough and ductile in the cold, which suits chillers and cold stores; PP is stiffer and more heat-tolerant for hot-wash regimes. For the full breakdown, read food-grade plastic explained.

A full-height vented bulk container is the workhorse of a potato or onion shed: roughly 455 kg of potato per bin, food-grade walls that hose down clean, and a heavy-duty base that stacks square for cold store and transport. Need a shallower bin for gentler crops or easier hand-filling? A low vented half bin drops the fill depth while keeping the same 1165-class footprint.

Can you store potatoes and onions in the same bin?

Use the same bin design, but not the same room. A vented bulk bin suits both crops, yet their ideal storage conditions pull in opposite directions, so they should be cured and held separately. Mixing them in one store shortens the life of both.

Onions want dry, moving air and lower humidity; they cure with warm airflow and then hold cool and dry. They also give off ethylene as they store.
Potatoes want cool, slightly humid conditions to limit shrink, and they are sensitive to ethylene — exposure can encourage sprouting and break dormancy early.

So the procurement decision is simple: standardise on one vented bin family for handling efficiency across both crops, but run two storage environments. The shared 1165-class footprint means the same forklift, the same racking and the same truck pattern serve both — only the room conditions change.

How do you choose the right vented bin?

Start from the crop and the shed, then match the spec. The three things that decide the right bin are how much it must breathe, what it must fit, and how it must stack and wash. Get those right and the rest is detail.

Genuine ventilation. For respiring crops like potato and onion, favour vented walls and an open or vented base, not a couple of slots. The deeper the load, the more the base venting matters.
Footprint. Match your handling — 1165 × 1165 mm is the common Australian bulk-bin footprint that palletises and squares up in cold store and on the truck.
Fill depth and volume. A ~470 L half bin is easier to hand-fill and gentler on delicate crops; ~700 L full bins and ~1,400 L boxes cut lifts per tonne for bulk potato.
Stack rating. Check the static (stacking) load rating against your store’s stack height — a bin that physically holds the crop still has to carry the bins above it.
Washdown. Open, smooth designs clean faster between crops and suit a HACCP regime.
Buy vs pool. Owning bins suits a fixed seasonal fleet; weigh it against rental for peak-only volume.

Browse the fresh-produce range or the full bulk containers category, compare volumes and load ratings in the product finder, or answer a few questions and let us recommend the right bin for your crop and shed.

Common questions

Why use vented bins for potatoes instead of solid ones?

Potatoes keep respiring after lifting, giving off heat, moisture and carbon dioxide. Vented walls and an open base let air move through the whole stack so the crop sheds field heat and stays dry. A solid-walled bin traps that heat and humidity in the middle of the load — exactly the conditions that drive rot, sprouting and shrink.

Can you store onions and potatoes together?

Not in the same room. Onions cure and store best in dry, moving air and give off ethylene; potatoes want cool, slightly humid conditions and are sensitive to ethylene, which can encourage sprouting. The same vented bulk bin design suits both crops, but keep them in separate stores with conditions tuned to each.

How many kilograms of potatoes fit in a vented bulk bin?

It depends on the bin volume and the crop’s bulk density (about 650 kg/m³ for bulk potato). A ~700 L vented bin holds roughly 455 kg, and a ~1,400 L vented pallet box around 910 kg. Onions pack lighter — closer to 550 kg/m³ — so the same bins hold fewer kilos. See our produce bin sizing guide for the full crop-by-crop maths.

Are plastic vented bins food-grade and HACCP-friendly?

Quality vented bins are moulded from food-grade HDPE or PP — smooth, non-absorbent surfaces that hot-wash and sanitise clean between loads, with no nails or splinters to end up in product. In Australia and New Zealand, food-contact materials sit under the food standards framework (FSANZ). That makes them a far better fit for a HACCP-aligned packhouse than absorbent timber field bins.

What is the standard Australian bulk bin size?

1165 × 1165 mm is the common footprint for Australian field and storage bulk bins. It palletises neatly and squares up in cold store and on the truck. Volumes step up on that base — a ~470 L half bin, ~700 L full bins, and bulk boxes around 1,400 L for denser, near-tonne loads.

Sources: FAO Platform on Food Loss and Waste and The State of Food and Agriculture 2019 (~14% post-harvest loss); Department of Agriculture, Fisheries and Forestry, National Food Waste Strategy (halve food waste by 2030); Food Standards Australia New Zealand (food-contact materials). Fill weights are indicative, calculated from bulk densities of ~650 kg/m³ (potato) and ~550 kg/m³ (onion); real fill varies with variety, grade, moisture and fill method. Crop-storage outcomes depend on your variety, climate and cold chain — treat this as general guidance, not a quote.