Mesh Bag

Most packaging conversations start from protection and treat ventilation as a concession. Mesh reverses the priority entirely: it starts from airflow and concedes everything else. For the commodities it serves, that is the right way round, because their dominant post-harvest risk is not impact but moisture-driven decay — neck rot and basal rot in bulbs, soft rots generally — and every one of those is favoured by trapped humidity around the produce surface.

A cured onion is also mechanically robust in a way a peach is not. It has a dry, tough outer skin, no exposed flesh, and it tolerates being tumbled and pressed to a degree that would destroy soft fruit. So the protection a mesh bag fails to give is protection the commodity does not need, while the airflow it does give addresses the thing that actually kills the crop. This is why the same bag would be an obvious absurdity for strawberries and is entirely correct for onions: the package matches the failure mode.

Mesh has a second advantage that has nothing to do with physiology. The customer can see the produce — all of it, not a top layer arranged over an unknown remainder. For commodities sold by the netful rather than the piece, that visibility does real work: sprouting, mould, and soft units are visible through the net, so a bad bag is identified before purchase rather than after.

The cost is that a net is a poor advertising surface. It carries a printed band or label rather than a printed face, so the brand has very little space to occupy — which is one reason mesh persists most strongly for commodities sold as commodities, where the produce is the proposition and there is little to say about it.

• Anything soft. There is no cushioning and no barrier: units press directly against each other and against whatever the bag is set down on.
• Anything that must not be exposed to light. This is decisive for potatoes, which green and accumulate glycoalkaloids on light exposure, and it is why light-excluding packaging is used for potatoes where mesh is used for onions.
• Anything needing a controlled internal atmosphere. Mesh is the opposite of modified atmosphere packaging: it guarantees that the atmosphere inside the pack is the atmosphere outside it.
• Anything that must be kept clean or contained. Dust, water, and contact with anything nearby all reach the produce freely.
• Load-bearing stacks. A bag of nets carries no structure; it slumps, and the produce carries whatever is on top of it.

The pattern is consistent enough to state as a rule of thumb: mesh suits produce that is hard, dry, cured, tolerant of light and handling, and at risk mainly from moisture. Move away from any of those and the bag stops making sense.

Most mesh bags are polyethylene or polypropylene net, and they are extraordinarily material-efficient — a net is mostly holes, so the mass of packaging per unit of produce is among the lowest of any package. That is a genuine environmental advantage and it is often overlooked, because a plastic net reads as plastic rather than as a small quantity of it.

The end of life is less favourable. Fine plastic net is a difficult recycling stream: it is light, it tangles in sorting machinery, it is contaminated with skins and soil, and it is frequently rejected from kerbside collection for exactly those reasons. It also fragments, and the same UV degradation that eventually destroys a discarded net is what turns it into persistent fragments. Cotton and other natural-fibre nets exist and biodegrade, and they cost more; where they are used, it is usually a market positioning decision rather than a technical one.