Sweet Peppers

A sweet pepper reaches full size while still green, and if left on the plant it will go on to develop its final colour — red, yellow, orange, or another depending on the cultivar. The grower chooses where to intervene. Picking at the green stage gives a saleable fruit early and lets the plant set more; waiting for colour means the fruit occupies the plant far longer, is exposed to more of what can go wrong, and blocks new set in the meantime.

Because the pepper is non-climacteric, that choice is final. There is no ripening room for peppers: a fruit picked green does not become a red pepper afterwards, whatever it is treated with — some green peppers will show partial colour break in storage, but this is not the even, full colour of plant-ripened fruit and does not produce a coloured-grade lot. Green and coloured peppers are effectively two commodities from one plant, separated by a decision made weeks before harvest and by the cost of the wait.

Sweet peppers are a warm-season fruit and are chilling-sensitive: held below the temperature they tolerate, they suffer chilling injury. It shows as surface pitting — small sunken lesions across the skin — along with water-soaked patches, discoloration around the calyx, loss of firmness, and a sharp rise in decay once the fruit is warmed again. As with other chilling-sensitive commodities, the injury generally appears after the cold exposure ends, not during it.

The commercial consequence is a squeeze. Peppers respire and lose water fast enough to want cooling, but cannot take the low temperatures that would slow those processes most, so the working regime is a compromise rather than an optimum. It also makes mixed storage hazardous in a specific way: a room set for the leafy vegetables it is mostly holding is set too cold for the peppers in the corner of it, and the peppers will pay for that days later and somewhere else.

Peppers are graded on colour and its uniformity, firmness, size and shape — blockiness and the number of lobes matter to the bell trade — wall thickness, and the condition of the stem and calyx, which buyers read as a freshness indicator. A shrivelled or blackened stem marks a lot as old regardless of how the fruit itself looks. Peppers are typically sized and graded on line, and the coloured trade is graded tightly because it is sold on appearance at a premium.

• Chilling injury — surface pitting, water-soaking, and calyx discoloration
• Blossom-end rot — a physiological disorder set before harvest
• Sunscald — bleached, papery patches on exposed fruit
• Shrivelling and softening from water loss
• Stem and calyx decay, and stem loss
• Bruising, cuts, and puncture damage from handling
• Uneven colour break on part-coloured fruit

The fruit is hollow, thin-walled, and easily punctured, and it is often cut with a stem that can spear its neighbour in the carton. Handling damage is therefore a standing loss in this commodity, and packing is designed around it — trays, liners, and shallow packs that stop fruit bearing on fruit.

Peppers are cooled after harvest to remove field heat, within the limit their chilling sensitivity allows, and held at high humidity because the fruit shrivels visibly as it loses water and shrivelled peppers do not sell. Film wrapping and modified-atmosphere packaging are widely used on coloured fruit to hold humidity and protect the surface, which matters more here than on most vegetables because the entire premium is cosmetic.

Peppers move refrigerated in cartons and trays, and mixed loads need care on two fronts: the temperature has to suit the most chilling-sensitive item aboard, and peppers are damaged by ethylene from co-loaded commodities, which hastens softening and decay. Compatibility here is about matching temperature regimes rather than defaulting to the coldest setting the truck can hold.