A label on a crate that goes into a cold room has to survive two things that ordinary labels do not: application onto cold plastic, and condensation forming on the surface afterwards. Most label failures on produce crates are one or other of those, not the adhesive quality.
Why cold is the problem
Adhesives need to flow slightly to wet out a surface. On a cold crate they do not, so the label sits on a film of air rather than in contact, and it lifts at the edges almost immediately.
The second issue is condensation. A crate coming out of a cold room into warm air collects water on every surface, and water between a label and PP is the end of the label.
What actually works
A low-surface-energy adhesive, formulated for plastics like PP and PE. This is the single most important choice and it matters more than the facestock. A standard paper label with a general-purpose adhesive will not hold, whatever else you do.
Apply at ambient temperature, to a dry crate. Label crates before they go into the cold, not while they are in it. That single change fixes most failures and it costs nothing.
Press the edges. Edge lift is how labels die. Firm pressure around the perimeter, with a clean dry cloth under your thumb, roughly doubles the life of a label on PP.
Where on the crate
A flat, unvented area, away from the base and away from the handle. The crate ends are usually the best surface; the base wears against pallets and conveyor rollers, and the rim gets grabbed.
Recessed label areas exist on some crates and they are worth specifying if labelling is important to you – a protected label lasts several times as long.
How long they last
In a cold damp loop with the right adhesive and correct application, a season is realistic. In a wash tunnel, much less, and labels are generally the wrong answer there – a printed crate or a tag is better.
Barcode labels and their survival is covered specifically in do barcode labels stay on PP picking boxes, which is the same problem in a different application.
Alternatives to labels
A printed or hot-stamped mark on the crate, which is permanent and needs no maintenance. A clip-on tag, which survives washing and can be changed. Or colour coding by crate rather than by label, which is crude and very effective when the number of categories is small.
Application temperature matters
Most adhesives have a minimum application temperature, commonly around five to ten degrees, below which they will not wet out. Applying a label to a crate straight out of a cold room is the single most common cause of immediate failure, and it is entirely avoidable.
Label at ambient, before the crate goes in. If that is not possible, use a cold-application label stock, which exists specifically for this and costs a little more.
One more thing that helps
Round the label corners. A square-cornered label on a curved or flexing crate starts lifting at the corner every time, and rounding them costs nothing but a pair of scissors.
What we can do
We make PP crates for fruit and vegetables with recessed label areas and can supply them printed or hot-stamped. Tell us how your crates get labelled and washed – we will say honestly whether labels are the right answer or whether printing is cheaper over the life of the crate.