Extension Educator, Horticulture
If a picture appeared next to the word "pucker," I'm sure it would detail the convoluted facial features of someone eating an unripe persimmon. Once I watched in dismay as someone ate a green persimmon. I think he would have eaten tree bark to remove the taste from his mouth.
Knowing when to harvest fruits and vegetables is a crucial part of gardening or grazing in the woods. It also protects you from practical jokes. For most fruits and vegetables the flavor and nutrition does not improve after harvest. Produce picked too early is likely to be tart and hard. Produce picked too late is likely to be tough, fibrous or mushy.
The sweetness of blackberries and raspberries rises dramatically as they ripen. These should be picked as the fruit becomes soft and sweet. The berry should drop into your hands with a slight pull. If you have to tug, the berry needs another day or so. If possible blackberries and raspberries should be picked every morning. As with most berries, store in a cool place after picking.
Apple harvest time will vary with the variety of apple and weather conditions. An indication of approaching harvest is when normal unblemished fruit begins to drop (diseased or insect damaged fruit will often drop before ripe) and when the flesh color at the bottom of the fruit has turned from green to yellow green. For the adventuresome a taste test will indicate the degree of sweetness.
Picking apples is done by rolling or twisting the apple to keep the fruit spur intact. Removing the branchlet or spur removes future apple production. Harvested apples should be kept cold at 33-35°F to retain maximum flavor and quality.
Ripe watermelons are a mystery to some. A combination of factors should be considered when determining ripeness: the light green curly tendrils on the stem usually turn brown and dry; the surface color of the fruit turns dull; the skin becomes resistant to penetration by a thumbnail and is rough to the touch; and the bottom of the melon where it touches the soil turns from light green to yellow.
The practice of thumping and listening for a dull thud is a better indicator of how full Uncle Harry is after Thanksgiving dinner than it is to the ripeness of a watermelon. Many watermelons do not emit a dull thud when ripe. For some watermelons a dull thud may indicate an overripe mushy melon.
Summer squash such as zucchini can get over-ripe quickly. Summer squash should be harvested while still young and tender about 6 to 8 inches in length and one and one half to two inches in diameter. Notice this is not the description of the baseball bat size zucchini found on your doorstep. Squash grow rapidly and are usually ready to pick 4 to 8 days after flowering.
The highest quality tomatoes develop when temperatures average 75°F. Tomatoes may get mushy and not color well when temperatures are above 90°F. During hot weather pick tomatoes when they have a healthy pink color and let them ripen indoors.
Pumpkins can be harvested when they develop a deep solid color (orange for most varieties) and rind is hard. Timing will depend on the variety so hopefully you kept the seed packet to know the days until harvest. Cut pumpkins from the vines carefully using a sharp knife and leave three or four inches of stem attached. Pumpkins that are not fully mature, have been injured, subjected to heavy frost or have no stem often do not store well.
Check out your University of Illinois Extension for the fact sheets FR-6-84 Harvesting Fruit or VC-11-80 Harvesting Vegetables or the publication Vegetable Gardening in the Midwest.