There are 14 to 18 bunches per 21 pound moisture-resistant carton. Average yields are 3 to 4 tons per acre in the south. Harvested broccoli must be cooled to 32 degrees F as soon as possible and is normally packed with ice in the cartons. Approximate storage life under these conditions is 10 to 14 days. If ice is not present in the container upon arrival, the shipment may be rejected by the buyer.
Broccoli heads produce ethylene, turn yellow and become unsalable at higher temperatures.
Ethylene from other produce, such as tomatoes and apples will also cause broccoli heads to yellow. Buttoning and Other Physiological Disorders Buttoning or premature formation of a small flowering head is caused by low temperatures. As with cabbage and cauliflower, the exact amount of chilling which will cause flowering is hard to predict and will differ with cultivar, plant age, and the duration of low temperatures. Generally, the plant stem must be at least -inch in diameter and temperatures must be 35 to 50 degrees F for several weeks to induce flowering. High temperatures during the day can counteract the effect of low night temperatures, however, making prediction difficult.