Many different aspects of the current food system prevent fruit and vegetables from getting to market, including crop shrink, a term used for the difference between the volume of edible crop available for harvest and the volume entered into commerce for human consumption.

The following are some of the most prominent drivers of crop shrink cited by survey participants in a new study commissed by the Natural Resources Defense Council:

Overplanting

Growers run a riskier-than-average business balancing weather, pests, and complex biological systems. Yet, they are required to provide dependable volumes that meet quality specifications to their buyers. As a form of insurance that they will have enough produce to meet their demand, growers often plant more than their expected sale volumes. At the root of this practice is the common perception that the cost of being short on an order is higher than the cost of planting and caring for buffer crop that may not get sold. Sometimes, this is literally true, but growers are also concerned about losing customers permanently if they are unable to fulfill on order in a given year.

Low market prices

Produce is often sold on the "spot market," where products are traded for immediate delivery without forward contracts. Prices vary significantly in this market, and growers sometimes face a tough decision just prior to the harvest window. Low spot prices can mean that the costs of harvesting a crop and getting it to market outweigh the revenue from its sale. When this is the case, a grower may decide to leave entire fields of harvest-ready product unharvested. These fields are known as "walk-bys" in the industry, and are particularly prevalent in years of high supply.

Labor shortages

Crops can be left unharvested when skilled labor for harvest cannot be found. Growers report that this challenge has increased in recent years.

Product grading

Cosmetic and quality considerations such as size, shape, color, blemishes, and ripeness also factor into whether product is sold, and at what price. In some cases, an entire block will be assessed to be below market-grade and become a walk-by. More commonly, harvesting crews are trained to pick to certain specifications, thus leaving small, misshapen, or otherwise lower-grade product in the field. For products which go to packing facilities, another quality check occurs there, resulting in further "culling," or removal of product.

Anticipatory packing

Processing and packing facilities often must anticipate their daily volumes in advance of receiving actual orders. When order volumes are not as large as forecast, extra packed product is left on the dock at the end of the day and must be gone before closing in preparation for the following day.

Shelf-life and spoilage

More broadly, the costs and logistics of ensuring that products remain refrigerated (which extends a product's life) make donating or finding other markets for produce more difficult, time-sensitive, and costly than, for instance, surplus clothing.