You spend all season tending to the needs of your vegetable crops—feeding, weeding, watering, and handpicking pests—and then comes the moment of truth: Has the fruit of your labor reached its peak of ripeness? We asked vegetable experts and market growers to share their secrets for selecting perfectly ripe produce and keeping it fresh. Take this guide with you to the garden (or the farmers' market), and you will fill your basket with the most flavorful food possible.
The Science of Freshness
A fruit or vegetable's existence depends on respiration—a physiological process in which starches and sugars are converted into carbon dioxide, water, and other by-products. Respiration continues after harvest, diminishing the starches and sugars that add flavor. Moreover, at harvest, vegetables are removed from their main oxygen source: their roots. This means postharvest respiration may be anaerobic (occur without oxygen). In anaerobic respiration, starches and sugars are more likely to be converted into ketones, aldehydes, and alcohols than in aerobic respiration. These compounds hasten the death of plant tissue and decrease the quality and flavor of fruits and vegetables. Gardeners can manage respiration—and the freshness of their produce—by using proper harvesting, handling, and storage techniques.
Beans Pay attention to your pods. Fresh, juicy, bright green pods indicate tasty broad, lima, and green shell beans. Snap beans should snap easily and have crisp pods with pliable tips.
- Harvest full-size snap bean pods before the beans begin to bulge.
- Pick daily for a continuous supply.
- Fresh tastes best—harvest beans right before you use them.
Broccoli and Cauliflower
Crucifers need to chill out for the best flavor. Pick them in the morning, cool them down immediately with ice or ice water, and then refrigerate, says Helen Harrison, Ph.D., professor of horticulture at the University of Wisconsin.
- Harvest compact, white, smooth cauliflower heads.
- Select blue-green broccoli heads and harvest them before the small, yellow flower buds open.
- Leave the small leaves on broccoli stems intact—they're very nutritious.
Cut cabbage heads off the stalk when they feel solid and hard to the touch.
- Want to keep mature cabbage in the ground a bit longer? Pull or twist the heads to break off some of the feeder roots and limit water uptake, and they will be less likely to split.
Here's a crop that can get better with age. Sugars increase in growing carrot roots for up to four months. This means tasty carrots can be harvested well into autumn in most areas. "You do have to watch out for splitting when it's real hot and dry or when it's too wet," says Pete Cashel of Terrapin Hill Farm Organics, in Harrodsburg, Kentucky.
- Dig full-size varieties when roots are ½ to 1 inch in diameter.
- Harvest storage carrots just before heavy frosts.
- Avoid selecting cracked or split carrots when buying at farmers' markets, says Cashel. They often have a bitter rather than sweet flavor.
Sweet corn—one of summer's most perishable crops—tastes best fresh from the garden (we're talking minutes here) and dripping with butter. If you can't prepare it directly after harvest, cool the ears on ice and then refrigerate them.
Harvest sweet corn about three weeks after the first silks appear. You'll know the corn is ready when the ears fill to the end with kernels and the silks and green husks become dry. An opaque, milky juice will seep out of punctured kernels.
- Snap off sweet corn ears with a quick push, pull, and twist downward.
- For a taste of summer in winter months, you can freeze sweet corn on the cob. Blanch and freeze right after harvest.
Frequent harvesting of cucumbers helps the vines produce new fruit. Why? Because one actively growing cucumber needs 40 percent of the plants photosynthetic output, says research from North Carolina State University.
- Pick bright green, firm slicing cucumbers when they reach 6 to 9 inches long.
- Detach cucumbers from the vine with a quick, upward snap.
- Quickly remove and compost any yellow, puffy, overripe fruit.
Ripe eggplants drain the plant's resources. So know what you grow and harvest eggplants when they reach the proper size for their variety.
- Select glossy eggplants that spring back when pressed. Overripe fruits don't spring back, have brown seeds, and taste bitter.
- Use shears to remove eggplants from the vine, says Willie Chance, University of Georgia extension agent.
Leo Keene, who with his wife, Jean, grows about 45,000 bulbs of garlic at Blue Moon Farm in Richmond, Kentucky, suggests using a square-tipped spade to dig garlic. "Your goal is to sever the roots," he says.
Dig about 4 inches away and parallel to the plant. Sink the spade 6 to 8 inches into the ground; then push to a near 90-degree angle, cutting the roots and lifting the garlic. Knock the dirt from the bulb and shade it immediately. "Garlic is easily sunburned," Leo Keene says.
- Start digging garlic when at least half of the top has died back.
- Leave tops intact and hang bulbs in a shaded, dry, well-ventilated area for two to three weeks—this process helps to preserve garlic for months.
Hot weather is a lettuce crop's worst enemy, because it causes bolting (the formation of seed heads) and bitter- tasting leaves. Luckily, you can often harvest tasty leaves from both head and leaf lettuce plants right up to bolting, Cashel says.
When buying lettuce at farmers' markets, look for vendors who display their lettuce on ice or in coolers, Cashel advises. And don't be afraid to ask if the vendors grew their own crops.
- Harvest lettuce in the morning to preserve the crispness it acquires overnight.
- Immerse lettuce immediately into cold water after cutting; then rinse and refrigerate.
- Cut leaf lettuce when outer leaves are 4 to 6 inches long; cut head lettuce when heads are moderately firm.
Pure melon flavor is short-lived and best enjoyed fresh. The more mature the melon, the less time it will keep in the refrigerator, though you can try freezing melons to preserve their summery sweetness.
- Harvest most muskmelons when the stem separates easily from the fruit. The skin between the netting turns from green to yellow at full ripeness.
- Honeydews soften slightly on the flower end of the fruit when ripe and change slightly in color.
- The belly of a watermelon turns from greenish white to buttery yellow or cream at maturity; also watch for the curly tendrils where the stem meets the melon to turn brown and dry.
- If you can't enjoy your melons right after the harvest, store them in a sealed container in the refrigerator, because their musky aroma can affect the flavor of nearby foods.
Do you crave homegrown produce in the winter? Then grow onions—they store for months when properly handled. Dr. Harrison says you should wait until the tops fall over to harvest, then gently dig up the whole plant and dry in a protected place.
- Leave the dry, papery outer skin on the onion; removal of that skin almost doubles the onion's rate of decay.
- Cut the onion tops off 1 inch above the bulb no sooner than four hours after harvest.
- Cure bruise-free onions for up to a month in a well-ventilated, dry, shady spot.
- Store onions in mesh rather than plastic bags.
The word pea should be synonymous with picking. Regular harvesting is vital because peas left too long on the vine arent as sweet and can impair the growth of immature pods. Sugar snap peas and traditional shelling peas should be fully formed but not overly large.
- Pick bright green, mature peas daily.
- Be gentle when pulling beans and peas from the vine—rough picking can jostle flowers off and damage vegetation. Some gardeners even snip peas off with pruners or small scissors.
Personal preference dictates when you pick peppers. Most peppers start out green and turn different colors as they mature. Harvest sweet peppers, such as bell peppers, and hot peppers at the degree of color you desire. And take care when picking—pepper plants damage easily.
- Pick pimiento peppers when they're fully red.
- Harvest hot Hungarian wax and sweet banana peppers when fully yellow, turning red, or fully red—depending on preferred hotness.
If you want to store potatoes, they need to be cured, says Jo Ann Robbins, Ph.D., University of Idaho extension educator. In this instance, curing doesn't refer to fixing a malady; rather, curing is the process that toughens potato skins for prolonged storage. Dr. Robbins recommends waiting one to two weeks after the plant tops have died back before digging the potatoes for storage. This cures the potatoes in the ground. Just be sure to dig them up before frost.
- Potatoes can also be properly cured after harvest if they are stored at 60° to 75°F and 80 to 90 percent relative humidity for one to two weeks.
- Don't wash potatoes you want to store—simply brush off the soil after it dries.
- Avoid exposing potatoes to light, which makes the tubers turn green and produce dangerous alkaloids.
Baby spinach is all the rage for a reason—the smaller leaves maximize flavor. "Most spinach tastes really good when it's 3 inches long," says Sondra Feldstein, who grows spinach and other vegetables on her farm in Bondurant, Iowa.
- Cut, don't pull, spinach to ensure multiple harvests.
Summer squash are notoriously prolific producers. "In some small towns, people lock their doors during the summer to keep out the zucchini" deposited by gardeners with a surplus, Feldstein says. Unless you want squash as big (and tasty) as baseball bats, you should pick them frequently.
- Small zucchini and yellow squash (6 to 10 inches long) and scalloped squash (3 to 6 inches in diameter) have the best flavor.
- Tasty fruits have tender rinds (they should puncture easily with a fingernail) and soft seeds.
Harvest tomatoes when the fruits are fully colored. At the end of the season, pick remaining mature green or pink tomatoes, put them on a plate or in a paper bag outside the fridge, and let them ripen.
- Pick fully ripe, but firm, tomatoes for juicing or canning.
- Harvest green tomatoes before a killing frost and ripen indoors.
- Store unbruised tomatoes out of the fridge for the best flavor, Dr. Harrison says.