* Pick vegetables at coolest time possible: cloudy days, early morning and evenings are best
* Harvest when produce is dry
* Be gentle so your produce won’t bruise
* Keep containers in the shade as you fill them
The quality of vegetables does not improve after harvest so it is important to gather crops at proper maturity. At this point vegetables are at their peak for flavor and nutrition. This is not always when a vegetable is at its largest stage. Check the garden frequently for ripe produce. Vegetables continue to grow and before long they are overgrown.
The ripe time varies with certain vegetables. Tomatoes may be left on the vine until fully ripened or taken off when partially ripened and placed on a windowsill to mature. Other crops such as winter squash and watermelon are not ready until after they are fully developed.
Harvest when pods are almost full size but before the seeds inside begin to bulge. Tips should be pliable. Beans should be crisp and snap easily. Harvest often.
Pick when pods and seeds reach full size and before pods turn yellow. End of pod should feel spongy. Pods and seeds should be fresh, juicy. Open a few pods to check. Use only seeds. Pods are tough and fibrous.
Beets can be eaten as greens when the leaves are 4 to 6 inches long. When grown for tops and beets, harvest when beets are 1 to 1-1/2 inches in diameter. To use only the beets, wait until they are 1-1/2 to 3 inches in diameter.
Gather when buds are compact and before buds turn yellow or open into flowers. (Some say to wait until the buds begin to loosen up.) Cut off 6 to 7 inches below flower heads. Small, tender leaves also are similar to collards and Scotch kale and are nutritious. More info at http://www.nwedible.com/2012/09/harvest-broccoli-cauliflower.html
Pick when sprouts (buds) at the base of plant are firm. Don¹t strip leaves since they are needed for growth. Pinch out growing point at top of plant to get larger sprouts.
Harvest when heads are firm and before mature heads split. Splitting is caused by excessive water uptake. To avoid this, give the head a quarter turn to break several roots.
Carrots are ready when 1 inch in diameter. They may be left in the ground for later harvest during cool, dry periods.
It’s ready when head is firm. It’s over mature when soft or when leaves turn yellow. When heads are a diameter of 2 to 3 inches, take outer leaves and fold them up and over the head. Tie them with a string. This keeps head from turning yellow. In 1 to 3 weeks diameter of head should be 6 to 7 inches and ready to harvest.
Pick when 6 to 9 inches long and still bright green and firm. Over mature fruits are dull in color or yellow and less crisp. For sweet pickles, fruits should be 1-1/2 to 2-1/2 inches long, and for dill pickles, 3 to 4 inches long. Do not raise vines when picking as this may damage the vines and reduce yields.
Harvest when 4 to 6 inches in diameter. Skin should be shiny, dark purple. Fruits are over mature when dull in color, soft and seedy.
Collards, kale, chard, mustard — Cut outer leaves when 6 to 8 inches long.
Pick when heads are moderately firm and about 6 inches in diameter.
Pods are ready when 3 to 4 inches long, about 4 to 6 days after the flower wilts. Pods stop producing if not picked, so gather them every 1 to 2 days.
Harvest when tops fall over and begin to die. Dig bulbs and dry for several days. Cut off tops and roots and store in a cool, dry place. Harvest green onions when they are 6 to 8 inches tall.
Peppers are shiny green in their prime and about the size of a baseball. They still are good after turning red or yellow. Hot peppers are red or yellow when ripe.
Sweet potatoes should be harvested before the first frost. Lift to avoid bruises and broken roots. Cure in a warm well-ventilated place for 2 to 3 weeks.
Pull them up when they are about 1 inch in diameter. Radishes become hot and tough when left in the garden too long.
Rutabagas are mature when 4 to 6 inches in diameter. They become woody and dry if soil is too dry.
Leaves are ready when 4 to 6 inches long. Pull out larger, whole plants or harvest older leaves to allow new growth.
Zucchini, cocozelle, crookneck, straightneck, scallop — Pick when seeds and fruits are small. Squash should be 6 to 8 inches long with skin you can puncture with a fingernail. Continue to harvest.
Winter Squash, Pumpkins
Butternut, buttercup, acorn, hubbard — Harvest when fruits are full size. Rind should be firm and glossy and bottom of fruit is cream to orange color. Leave squash on stems for better storing and pick before fall frost.
For canning or juice pick fruits that are fully colored. If cracking at the top is a problem in hot weather, pick them when they are turning pink. These tomatoes will ripen in the shade indoors. Before the frost, pick green tomatoes and store in a dark place where they can ripen.
Harvest when roots are 2 to 3 inches in diameter but before the frost. When grown for greens, pick leaves when 4 to 6 inches in length.
(Most of this info is from University of Illinois Extension)