Harvest timing for tree fruit crops varies based on the fruit type and variety. Various fruit maturity-testing methods are used to help determine when fruit are ready for harvest. Some methods also indicate which fruit will go straight to the market versus those that will be cold stored until marketing at a later time. Some types of fruit cold store better than others, whether in regular atmosphere (RA) or controlled atmosphere (CA) conditions. For storage purposes, some fruit are picked at early maturity with good quality and they are further ripened while in storage.
Individual orchard blocks of fruit should be evaluated and tested separately to determine maturity. To ensure optimal fruit quality, some trees may require multiple harvests. For example, fruit located at the canopy periphery on limbs that are well exposed to the sun will mature sooner than fruit on shaded limbs in the interior of the tree canopy. This is particularly the case for larger, older trees with extensive canopy volume.
A general seasonal benchmark that growers often use for estimating fruit maturity date is “days after full bloom” (DAFB). This reference can be especially useful if DAFB was recorded for harvest dates for that particular block in previous years. Depending on weather, the actual DAFB value may vary from 5 to 20 days or so from one year to the next. Ideally, maturity testing begins two weeks or more before estimated time of harvest and continues each week until harvest. Fruit firmness, soluble solids concentration (SSC) and starch content are among the primary tests performed at this time. Fruit size, taste, and skin coloration are also considered when making harvest decisions. Advancing maturity is indicated when values of each measurable parameter begin to change from week to week. In apples, for example, as fruit mature, firmness will decrease, SSC will increase and starch content will decrease (starch iodine test value, noted later, will increase).
The field horticulturist makes harvest decisions based on fruit volume, maturity, color, size and orchard history and then communicates these decisions to the warehouse. Fruit segregation, storage and marketing decisions are most accurately made through frequent and detailed communications between horticulturists, warehouse receiving personnel, storage and quality control personnel and marketing staff. Adjustments in harvest timing and the rate of harvest progress might be necessary to meet storage and marketing goals.