James C. Schmidt
Extension Specialist, Home Horticulture/4-H
University of Illinois Extension
One of the most important phases of vegetable gardening involves knowing when to harvest the produce. The quality of vegetables does not improve after harvest so it is important to gather the crops at the proper maturity when that are at their peak for flavor and nutrition. Garden produce that is picked too soon is too tender and lacks substance and flavor. Picked too late, it is likely to be tough, fibrous or mush, and also lacking in flavor.
The time for harvesting varies with climate, the particular season, the variety, and the vegetables involved. For instance, tomatoes can be left on the vine until fully ripened or taken off when partially ripened. Other crops such as winter squash and watermelon are not ready until after they are fully developed The “days to maturity” listings on seed packets and in gardening books and seed catalogs are helpful. But many variables involving these figures are given in general terms, so the numbers should be used only as guidelines.
Some suggestions for harvesting 34 common vegetables at the time they provide the most delicious eating follow. Check the garden frequently for ripe produce during harvest time since vegetables continue to grow. When harvesting, avoid bruising or damaging the vegetables which causes decay.
Asparagus - Asparagus can be harvested the third year after planting crowns, but do not harvest for more than one month the first time. In the following years, the spears may be harvested in May or June. Harvest spears 5 to 8 inches tall by cutting them or snapping them off. Cutting may damage some spear tips that have not yet emerged from the ground. To snap a spear, bend it from the top toward the ground. Asparagus deteriorates rapidly after harvest. If it is not eaten immediately, it should be processed or refrigerated.
Lima Beans - Pick lima beans when the pods are well-filled but before they turn yellow. The end of the pods should feel spongy.
Snap Beans – Snap beans are best when the pods are firm and snap readily, but before the seeds within the pod develop. The tips should be pliable.
Beets – Harvest beets when they are 1¼ to 2 inches in diameter. The beet tops can also be eaten as greens. The leaves should be 4 to 6 inches long.
Broccoli – Cut broccoli when the buds are compact but before they turn yellow or open into flowers. Leave 5 to 6 inches of stem attached. Side shoots that develop in the axils of the leaves can also be harvested.
Brussels Sprouts – The small sprouts may be picked or cut when they are firm and about 1 inch in diameter. Pick the lower sprouts as soon as they are large enough for use. Lower leaves may be removed to allow more room for sprouts to develop.
Cabbage – Cut the heads when they are solid, but before they crack or split. In addition to harvesting the mature heads, you can harvest a later crop of small heads or sprouts that develop on the stumps of the cut stems. The sprouts will be 2 to 4 inches in diameter and should be picked when firm.
Carrots – Carrots are ready for use when they are young, crisp, and ½- to 1 inch in diameter. The sugar content is higher in mature carrots, but the younger ones are more tender. Carrots planted in the summer may be left in the ground until a killing frost, when they become very sweet. A straw mulch can be placed over the row so that carrots can be harvested until the ground freezes solid.
Cauliflower – Harvest before the head become over-mature and “ricey.” The heads should be compact, firm, and white. To keep the head white, tie the outer leaves together over the center of the plant when the head begins to form. Cauliflower will grow 6 to 8 inches in diameter and is ready for harvest 7 to 12 days after blanching.
Chard – Use the leaves as they become 8 to 10 inches long and are still young and tender. New leaves will continue to grow from the center of the plant.
Chinese Cabbage – Cut the entire plant at the ground line when the heads are compact and firm. Harvest before the seed stalks form in the early summer, and before freezing temperatures in the fall.
Corn – Pick corn when the silk turns dark and starts to shrivel. The kernels should be bright, plump, and milky. This stage occurs about 20 days after the appearance of the first silk strands. To harvest, snap off the ears by hand with a quick, firm, downward push; then twist and pull. Corn is at its prime eating quality for only 72 hours before becoming over-mature.
Cucumbers – Cucumbers may be picked when they are 2 inches or long or less for pickles, 4 to 6 inches for dills, and 6 to 8 inches for slicing varieties. A cucumber is at its highest quality when it is uniformly dark green, firm, and crisp. Cucumbers are past prime if they are large, dull, puffy, and yellow. Remove old fruits from the vine so that young fruits will develop.
Eggplant – Harvest eggplant when the fruits are 6 to 9 inches long, glossy, and have uniformly deep color. The fruits are over-mature when they become dull, soft, and seedy. Use a knife or pruning shears to cut the fruit off the plant. Leave the green calyx attached to the fruit.
Endive or Escarole – Cut the plants at the ground level when they are fully developed (10 to 12 inches across) and the center leaves have been blanched.
Garlic – Pull up the bulbs when the tops start to yellow and dry. Place the bulbs on screens to dry. When dry, trim the roots close to the bulb, remove the loose, outer sheaths, and store under cool, dry conditions.
Horseradish – Dig the roots anytime from late fall after a hard freeze until growth starts in the spring.
Jerusalem artichoke – Dig the tubers anytime from September until after a frost, and in the spring before the new growth starts.
Kale – Break off the outer leaves as they become 8 to 10 inches long. New leaves will continue to grow from the center of each plant.
Kohlrabi – The best time to harvest is when the bulbous part is 2 to 3 inches in diameter (size of a golf ball). Large, older kohlrabi is tough and woody, and may have an off flavor. The young leaves can be cooked like spinach.
Leek – Harvest in late summer and fall by loosening the soil with a spading fork and pulling out the plant. Cut off the roots and all but 2 inches of the green leaves.
Lettuce – Leaf lettuce reaches maximum size in 50 to 60 days after planting. Cut or pull the outer leaves (4 to 6 inches long) as you can use them. Butterhead varieties form small, loose heads that are ready in 60 to 70 days.
Muskmelon – This type of melon develops the best flavor when ripened in warm, dry weather. As the melon ripens, the stem separates readily from the fruit. After harvesting, the fruit can be held at room temperature for 1 to 3 days until the blossom end softens.
Mustard – Harvest the leaves when they are young and tender, about 6 to 8 inches long. In the summer, the leaves become tough and develop a strong flavor.
Okra – The okra pods should be harvested while they are immature and still tender (2 to 3 inches long). The larger pods will be tough and woody. The pods must be picked at least every other day if you want the plants to remain productive.
Onion – Green onions (scallions) may be harvested when the tops are 6 inches high and the stem is the thickness of a pencil. Harvest dry onions in late July or early August after most of the tops have fallen down. Allow the bulbs to air-dry in a warm location on slats or screens. Complete drying or curing takes 2 to 3 weeks. After curing, the onions can be braided in bunches, or the tops can be cut to 1½- to 2 inches long.
Parsnip – Parsnips should be left in the ground until the tops freeze, since they are not fully flavored until after an early frost. The moderate sizes are best; larger ones may be woody. You can leaves the roots in the ground and place a deep layer of straw mulch over them so that you can dig throughout the winter.
Pea – Pick peas when the pod is full and green, and the peas are still tender and sweet. Test for maturity frequently by picking a couple pods and examining them for firmness. Harvest the Chinese and snow peas, which are eaten pod and all, when the pods are 1½ to 2 inches long and the peas are about the size of BB’s. The pods are usually picked 5 to 7 days after flowering.
Peanuts – Harvest in early to mid-October, before a hard freeze. The plants are mature when they turn yellow. Dig up the entire plant and shake the soil off the peanuts. Cure them by stacking the plants in an open shelter or by hanging them in a warm, dry shed or garage for a week. After the plants have dried, shake off any remaining soil and pull the peanuts from the vine. Continue to air dry for another week or two. When the peanuts are dry, they are ready to shell or roast.
Peppers – Fruits may be harvested at any size, but they are usually picked when they are fully grown and mature. They may be left on the plant to ripen fully to a red or yellow color, in which case they have a sweeter flavor. Hot peppers, except Jalapeno, which remains green when ripe, are usually harvested at the red ripe stage.
Potatoes – “New” potatoes can be dug before the vines die. For large potatoes, wait until the vines die. Use a spading fork to dig 4 to 6 inches below the soil surface. Handle the tubers gently during harvest to avoid bruising, which reduces length of storage.
Pumpkins – Allow the fruit to ripen fully on the vine, but pick them before the first heavy freeze. The fruit should have a deep-solid color and a hard rind. Cut pumpkins from the vine, leaving 3 to 4 inches of stem attached. Pumpkins without stems do not store well. Store in a cool, dry area (50° to 55°F).
Radish – For best flavor, start thinning and eating radishes when they are the size of marbles. They will be good up to 1 inch in diameter. After that, they become hot and pithy.
Rhubarb – Do not harvest the first year of planting. In the second year, harvest only for 1 to 2 weeks. Thereafter, stalks may be harvested for 8 to 10 weeks. To harvest, pull the leafstalks from the plant. Only the stem (petiole) is used, since the leaves contain large amounts of calcium oxalates and should not be eaten.
Spinach – Spinach may be harvested from the time the plants have 6 to 8 leaves until the seed stalk develops. For best quality, cut the entire plant off at the soil surface.
Squash – Summer squash should be harvested while still young and tender – 6 to 8 inches in length and 1½ to 2 inches in diameter. Scallop squash are best while small, 3 to 4 inches in diameter and a grayish or greenish-white in color. Squash grow rapidly and are usually ready to pick 4 to 8 days after flowering. Harvest winter squash when the vines have died back and the fruit has a hard rind, but before a heavy frost. Cut squash from the vines carefully, leaving 2 inches of stem attached to ensure longer storage. Avoid cuts and bruises that reduce shelf life.
Sweet Potatoes – Harvest in the fall before frost kills the vine. Handle carefully when digging to avoid bruises. After digging, let the roots lie exposed for 2 to 3 hours to dry thoroughly, then put them in a warm room at 85o F. to cure for about 10 days.
Tomatoes – During hot weather, pick the tomatoes when they have a healthy pink color and let them ripen indoors. Otherwise, leave them on the plant until the fruit has fully developed color. If you have green fruit on the plants in the fall when frost is approaching, pick the tomatoes and store them in a cool, dark place to ripen.
Turnips – Harvest when the roots are 2 to 3 inches in diameter. The tops can be used for greens when they are 4 to 6 inches long. Turnips can be left in the ground in the fall and mulched with a deep layer of straw for harvest during early winter.
Watermelons – Use a combination of the following indicators to determine when watermelons are ripe; (1) light-green, and when the curled tendril near the stem begins to shrivel and dry up; (2) the surface color of the fruit turns dull; (3) the skin is rough and resists penetration by a thumbnail; and (4) the bottom of the melon where it touches the ground turns from a light green to a yellowish color. Watermelons will not continue to ripen after harvest.