By B. Rosie Lerner Purdue News Service
---- — Nothing beats fresh-picked vegetables picked from the garden, but timing is everything! Harvesting at the right stage is essential - proper storage will help maintain homegrown freshness.
Some crops are best harvested frequently while still immature, while others need to mature as long as possible. Crops also vary in their optimal storage requirements; some do best in cold, moist storage; others do best in dry storage.
The following crops are grouped by similarity of storage requirements.
Cold And Moist (32-40 degrees F)
Beet tops make excellent tender greens when roots are no more than 1 inch in diameter. If harvesting primarily for roots, begin digging when roots are 2-3 inches.
Carrots come in a wide range of sizes, shapes and even colors. Root quality will be best while on the young side; older roots get woody. Note the days to maturity listed on the seed packet. Fall-harvested carrots should be dug before the first moderate freeze.
Turnips can be harvested from the time they are 1 inch in diameter. They are best as a fall crop and can withstand several light freezes.
Broccoli should be harvested while the individual flower buds are still tight and of good green-blue color. After the main central head is cut, smaller heads will develop from side shoots.
Brussels sprouts should be cut as the small heads develop in the leaf axils, beginning at the bottom of the stem. Sprouts can withstand several moderate freezes; in fact flavor is said to improve after frost. Harvest all sprouts prior to the first severe freeze.
Cabbage should be harvested when heads are solid and full-sized for the cultivar.
Cauliflower is usually ready to harvest about two weeks after the heads appear. To keep heads white, tie outer leaves above the head when curds are about 1-2 inches in diameter (except purple types).
Muskmelon (cantaloupe) should be harvested when the rind changes from green to tan or yellow between the outer netting, and the stem slips easily from the fruit.
Summer squash should be harvested while fruits are young and tender-skinned, 6-8 inches long or 3-4 inches in diameter for round types.
Sweet corn is best harvested when kernels are plump and tender and yield a milky juice when pressed with your thumbnail. Kernels that are past their prime tend to yield thick, doughy pulp, while immature kernels will yield a watery juice.
Cool and Moist Storage (45-50 degrees F)
Cucumbers are best harvested while immature and before seeds have a chance to fully develop. The timing will vary with the cultivar. Most slicing cultivars will be 1 1/2-2 1/2 inches in diameter and 5-8 inches long. Pickling cucumbers will be short and blocky, compared to slicers.
Eggplants are best harvested when fruits are nearly full grown but while they are still immature; they get seedy rather quickly. Eggplants are not adapted to long storage.
Green bean pods will be most tender when the small seed inside is one-fourth mature size and not yet visible from the outside. Past this stage, the pods become more fibrous as the seeds mature.
Okra should be harvested daily as young, immature pods when they are 2-3 inches long; the pods get woody if allowed to mature on the plant.
Peppers, both bell and hot types, are usually green while immature and red, or some other color, as the fruit matures. They can be harvested when fruits are firm and full size. Picking them while green will encourage further flowering and fruit set. If red (purple, yellow or orange for some varieties) fruits are desired, leave on the plant until color develops.
Potatoes can be harvested as “new” potatoes, before maturity, if they are going to be consumed right away. If storage potatoes are desired, harvest after the tops have yellowed and/or died back. Carefully dig the underground tubers, and then cure (air dry) for about a week in a shaded, well-ventilated place (open barn, shed or garage). Remove excess soil from potatoes, and discard those that are diseased or damaged. Avoid exposing tubers to light; they will turn green with even a small amount of light. Store in as cool a place as possible but above 40 degrees F. Ideal storage conditions are hard to find in late summer - cool basements are often the best storage available. Keep humidity high and provide good ventilation.
Tomatoes harvested ripe from the garden will keep for a week, but most refrigerators are a bit too cold. For best quality, they should be stored at 45-50 degrees F. Green mature tomatoes can be harvested before frost and stored at between 55-70 F. For faster ripening, raise temperature to 65-70 F. Mature green tomatoes can be stored three to five weeks at 55-58 F. Wrap each tomato in newspaper, and inspect frequently for ripeness.
Watermelon can be really challenging to guess when ready. I find the most reliable cue to be what is called the grounds spot, when the underside of fruit that was touching the ground turns from whitish to yellowish. The tendril at the juncture of the fruit stem and the vine usually dies when the fruit is mature. Thumping an immature melon gives a ringing, metallic sound while a mature melon gives a dull thud.
Cool, Dry (45-55 degrees F)
Onions for storage should be dug when two-thirds to three-fourths of the tops have fallen over, and the necks have shriveled. Remove tops, place in shallow boxes or mesh bags, and cure in an open garage or barn for three to four weeks. Store in mesh bags in a cool, well-ventilated location.
Warm, Dry (55-60 degrees F)
Pumpkins and winter squash are harvested when mature but before frost - the rind is hard and the colors have darkened.
Warm, Moist (55-60 degrees F)
Sweet potatoes should be harvested in the fall before frost kills the tops. Carefully dig the roots and cure for one week in a warm, well-ventilated location, 80-85 degrees F before storing.
For more information on growing and harvesting vegetables, see Purdue Extension’s “Home Gardener’s Guide” (HO-32) http://www.hort.purdue.edu/ext/ho-32.pdf.