Vented bulk bags

Walls that breathe

A vented bag starts as a standard uncoated four-panel or circular body. The difference is in the walls: vertical bands of loosely woven, open fabric run from the floor to the rim, sewn in between sections of the normal weave. Air passes through those bands. The rest of the wall, the floor and the loops carry the load as in any FIBC.

Coating would close the very gaps the bag relies on, so vented bags are uncoated, and they never carry a liner.

The rating on the label comes from tests of the whole bag, vents included. Don't pile on extra weight because a bag of potatoes looks less full than a bag of sand; the SWL is the limit whatever the volume.

Strip width and spacing vary by maker and product. Wider, more open bands move more air but hold small pieces less well; narrower bands suit little onions or kindling. A sample filled with your own crop shows the balance better than a spec sheet.

Produce and firewood need different things

Potatoes and onions are alive after harvest. They respire, giving off moisture and heat, and a tightly closed bag would let both build up in the middle of the load. Vents let that air escape, and the bag is gentle enough to fill from a low conveyor without bruising the crop. Produce goes in new bags only, since it's food.

Firewood is the opposite case: it is drying, not respiring, and it often sits in a yard for a long time. Vents help it keep drying in the bag. The risk is the sun. UV exposure softens and powders polypropylene, and bags left outside for a long spell shouldn't be lifted. Store filled firewood bags under cover where you can, and inspect the loops and fabric before each lift.

Timing matters with the crop. Onions need dry, cured skins before bagging, and potatoes are usually cured before long storage. Bag after those steps, not before, so the vents carry away ordinary respiration rather than field moisture and soil.

Filling gently and emptying in one go

For potatoes, keep the drop height short and let the crop roll in from a conveyor end or a bin tipper with the bag hung on a frame. A duffle top can be gathered loosely or left open in a ventilated store. For firewood, a wide open or duffle top lets a conveyor or a person stack wood in quickly.

At harvest, potatoes coming off a harvester or grading line usually ride a conveyor into bags staged on frames, while woodlots often fill straight from a firewood processor's outfeed belt.

Most vented bags have a flat floor and are emptied by lifting over a bin and cutting the bottom, or by tipping firewood out at the customer's site. Some produce bags use a wide discharge spout that opens fully for a quick, gentle release.

Potato and onion stores often run forced-air ventilation through stacked bags, and the open strips give that airflow a path into each one rather than only around the outside of the pile.

Vented, standard uncoated or mesh

A standard uncoated bag breathes a little through its weave, which is enough for gravel and plenty of dry goods but not for a load that's producing heat. Vented strips move far more air. Leave them out for anything fine enough to sift, and for any product that must be kept dry.

Firewood dealers often deliver the filled bag itself to a customer's driveway, set down by a forklift or truck-mounted crane, which saves handling and restacking the wood twice.

Seasonal loads and the request

Produce growers and firewood dealers tend to need bags in a burst, before digging starts or before the heating season. Plan the order early, because the bales have to be on your floor before the crop comes in. Vented bags fold and bale like any other, on wrapped pallets, LTL or full trailer. Send us the product, the smallest piece, the fill weight, the top and bottom, the storage plan and the ZIP, and we'll lay out the load and confirm a delivery day with the carrier.

• Crop or wood species
• Smallest piece size
• Fill weight
• Top and bottom
• Storage: shed, yard or under cover
• Delivery ZIP and the date the bags must be on hand