Stem vegetables are also hand harvested. A limited amount of asparagus has been experimentally machine harvested. Maturity of floral vegetables is determined by head size and development. Field Packing Field packing is used for all leafy vegetables, except Brussels sprouts. The products are selected for maturity and quality, and then cut, trimmed, packed in cartons or crates, transported to cooling facilities, cooled, put into temporary cold storage prior to loading or loaded directly, and transported to market.
Field packing generally provides greater marketable yields because of reduced mechanical damage.
Wrapped and unwrapped lettuce, celery, cauliflower, broccoli, and spinach are mostly field packed, though the latter three are still packed in packinghouses by a few shippers. Small celery stalks may be trimmed and packed as hearts in the field or field packed in bulk containers after harvesting and transported to packinghouses for trimming, sorting, prepackaging, and packing as celery hearts. Wrapped lettuce and cauliflower are hand selected, cut and trimmed, and then placed on mobile field units where they are wrapped and packed into cartons. They are then palletized and transported to the cooling facilities for cooling and subsequent handling. Rough handling in field packing is a mayor cause of lettuce and cauliflower marketing losses.