Harvesting Vegetables for Best Quality

A vegetable gardener reaps the benefits of their hard work by putting delicious and nutritious food on their table. It won’t help to go to all that work, however, if you do not harvest at the right time. Harvesting properly is very important to getting the best quality vegetables from your garden.

Some vegetables are harvested while immature, such as bell peppers and zucchini. Other crops, such as tomatoes and sweet corn, are harvested when ripe and have a shorter period in which harvesting should be done for best quality.

The best quality is maintained if the vegetables are consumed soon after harvest. When harvesting, you are removing a plant part that becomes a separate living entity. As a separate entity, the vegetable uses energy from its stored food reserves and loses moisture through transpiration. Vitamin content also decreases during storage. Most vegetables should be refrigerated as soon as possible to slow down respiration and water loss. Exceptions would be Irish potato, tomato, melon, garlic and onion, which should be stored at room temperature to maintain high quality.

Harvesting should be done in early morning if at all possible. The later in the day you harvest, the more "field heat" has built up within the vegetable. This will cause vegetables to take longer to cool in the refrigerator, thus reducing quality. If late day harvesting is necessary, you can place the vegetables in ice water for quick removal of the heat, then store in your refrigerator. The faster you cool them down, the longer you can successfully store them.

When storing leafy or root vegetables in the refrigerator, they should not be stored with fruits. Fruits give off ethylene gas which reduces the quality of your vegetables. For example, ethylene will cause yellowing of green vegetables, russet spotting of lettuce and bitter taste in carrots.

All refrigerated vegetables should be used within five days for best quality and nutritional content. 

Recommendations on harvesting for specific vegetables are as follows:

WARM SEASON VEGETABLES

• Snap beans should be harvested when pods are still tender and beans are very small. If beans are allowed to mature on the plants, they can be shelled and cooked as dry beans.
• Sweet Corn should be eaten as soon as possible after harvesting. As soon as the ear is harvested, the sugars begin converting to starch. Generally, sweet corn is at its peak for 2 to 3 days. Harvest when the silks turn light brown to brown. You can peel back the shuck to see how developed the kernels are before removing the ear. The juice of the kernel should be milky when you puncture it with your thumbnail. Remove the ear firmly holding the ear with one hand and the stalk with the other hand. Quickly twist the ear and it will separate from the plant.
• Cucumbers can be harvested at your desired size; however, harvesting should be done before the cucumber begins to lose its green color. Old cucumbers will begin to yellow and have well developed seeds. Often, they become bitter when over mature. If fruit is allowed to mature on the plant, the plant will stop producing new fruit.
• Eggplant should be harvested when they are one-third to two-thirds full mature size. The skin should be glossy. If the skin is dull, this indicates over maturity; the fruit will be seedy and often bitter. Harvest using pruning shears since the stem is tough.
• Peppers, both sweet and hot, can be harvested at any size. Nearly all peppers will turn red at maturity. Allowing peppers, especially sweet peppers, to mature on the plant will lower fruit set.
• Tomatoes can be harvested any time after the "white stage". This is the stage where the dark green fruit fades to a pale green or almost white color. Best quality is obtained when fruit are allowed to fully ripen on the plant. If early harvesting is done, ripen the fruit at room temperature without any direct sunlight.
• Okra should be harvested every 2 to 3 days. Most varieties should be harvested when they are less than 3 inches long. The pod snaps easily from the plant unless it is over mature.
• Summer squash should be harvested while the skin is still tender. The skin should be easy to puncture with a thumbnail. The more frequent the harvesting, the more fruit the plant will produce. Use a knife to remove the fruit leaving one inch of stem attached.
• Winter squash (pumpkins, Hubbard, butternut, acorn) should develop a tough skin before harvesting. If too immature, the sugars will not have been stored and the squash will have a bland flavor. The rind should be hard and cannot be punctured with a thumbnail.
• Watermelons are a bit tricky and require some experience. Look for the small tendril where the watermelon stem attaches to the vine to shrivel up. The skin will go from shiny to dull. The belly of the watermelon where it lies on the ground will turn from white to creamy yellow or yellow.

Prepared by: Dan Gill, LSU AgCenter Consumer Horticulturist