Produce generally available to us at the local big-box grocery store is anything but “peak ripeness”. Most fruits and vegetables are picked early so that they ripen while in transit from another country or at best the other side of the US. Others are picked early and forced to ripen by artificial means, greatly impacting the flavor and nutrient value of the product. Vegetables are grown as monocultures and harvested all at once, some more ripe than others. How can we be sure that what we are eating is anywhere near it’s peak of flavor or nutrition?
Identifying peak ripeness has utility in the garden as well. Some fruits can be relatively easy to identify as the exterior color tells us how ripe the fruit is. Others must be handled to feel the softness of the skin, or firmness of the fruit inside. Other produce may develop a particular scent when they’ve reached ripeness, a scent that often changes again once they’ve gone past their peak. Then there’s the taste test…the ultimate test of ripeness. Unfortunately, we can’t taste fruit still on the vine or in the grocery store before we choose it.
Below we’ll review some techniques for identifying ripeness, then cover some identifiers of ripeness in some common garden favorites.
Techniques for Determining Peak Ripeness:
The Brix scale is the ratio of sugar to liquid in the fruit which increases as it ripens, so if the Brix number is higher, the fruit is sweeter. So how is the sugar to liquid ratio measured? A refractometer, which is a telescope-looking contraption, uses a speck of the fruit’s juice to measure the Brix ratio. Different fruits have different Brix concentrations, we can use this chart to compare varying ripeness levels for fruits ranging from apple to watermelon.
For some fruits such as apples, a starch/iodine test can be performed on a sample batch to determine ripeness. The test takes halved samples of apples from harvest trees and uses an iodine solution to stain the starches in the fruit to visually demonstrate sugar and starch ratios. Similar to the Brix testing, determining ripeness has much to do with identifying sugar content as an indicator of ripeness.
Aside from technical tests for sugar content, there are also a multitude of visual cues anyone can use to determine ripeness. Looking for things like rich color, healthy textures, crispness and fullness in a fruit will help indicate ripeness. It would require some prior knowledge or experience with the fruit in question to know what you’re looking for.
Ultimately, taste is the greatest indicator that the produce is ripe and ready to consume. Tasting for freshness and ripeness takes experience and practice. You’ll know pretty quickly if the flavor is off, sour, bitter or tasteless that you’ve missed the ripeness window. Luckily, when most people have tasted a perfectly ripened fruit they will remember what that tastes like and be able to judge peak ripeness based on that experience.
Peak Ripeness in Common Vegetables:
Baby Greens – Harvest baby greens at any time once the leaves have reached 2 to 4 inches. Look for undamaged, richly colored leaves. Baby greens usually have a sweeter, more delicate flavor than mature greens. Cut and come again varieties will continue to produce if not over harvested. If the plant bolts or greens begin to taste bitter, it is time to replace the plant.
Mature Greens – Examine green- and red-leaf lettuce varieties for ripeness about 50 to 60 days after planting, or when the outer leaves grow to between 4 and 5 inches tall. Ripe leaf lettuce develops rich-colored, well-ruffled and deeply lobed leaves upon maturity. Harvest leafy greens early in the morning when they are holding the most moisture.
Examine butterhead lettuce varieties for ripeness between 60 and 70 days after planting, before any of the plants bolt. Pull loose leaves away from the base of a few various heads. Grab each head in both hands and squeeze it gently. Ripe head lettuce has a firm, full feeling in your hands, indicating it has developed completely in the center and has little space between the layers. The outer leaves should wrap tightly around the head.
Check romaine varieties of lettuce for ripeness between 50 and 75 days after planting, or when they reach at least 6 inches tall and have a 3-inch wide base. Ripe romaine has an elongated shape, with dark-green outer leaves that ripple along the edges. Break off a leaf of romaine and listen for the telltale “snap,” which indicates the peak of crispness and water retention in the white center rib. Ripe inner leaves of romaine overlap and look densely packed to the core.
Examine stem lettuce when the stalks reach about 6 to 8 inches tall and 1 to 1 1/2 inches in diameter. Upright-growing stem lettuce develops thin, deep-green foliage on top of the stem and has tightly packed papyrus-like layers of fiber around the stalk.
Microgreens – Microgreens should be harvested right before they begin to develop their first set of true leaves. The nutrient benefit in microgreens is taking advantage of all that stored energy and nutrients the plant would use to grow those first leaves. Height, size and color would all depend on the type of microgreen.
Beans – Taste one and decide. You may want to start harvesting French snap or string beans when they are about the diameter of a chopstick, maybe even thinner. Standard varieties are ready when they are as thick as a pencil and before the seeds swell and become visible through the pods. Lima beans are ready when their pods take on a green color and feel full. When bean pods turn white, feed them to the pigs or the compost pile.
Broccoli – The buds (treetops) should be dark blue-green and tightly closed. If the underside of the top turns yellow, the broccoli is overripe. The stalks should be firm and the greens should be green and fresh (not limp).
Carrots – Young carrots are the sweetest. Carrots are mature at ½ inch in diameter. Look for a bright color, firm body, and smooth skin. The leaves should be crisp and green.
Cucumbers – Harvest when about 6 inches long. Look for richly dark green skin and a heavy, firm body. Small cukes are the sweetest and have the softest seeds.
Onions – Harvest green onions when the bulbs are 1 to 2 inches in diameter. Wait for the tops of storage onions to fall over and turn brown before you pull them.
Garlic – The wrapper or “paper” should be unbroken, tight, and dry (not disintegrate). When harvesting, the tops will turn yellow. The bulb should be firm and plumb, not shriveled or spongy. Avoid sprouts.
Tomatoes – Leave your tomatoes on the vine as long as possible. The perfect tomato for picking will be very red or rich in color, regardless of size. A ripe tomato will be firm and plump—only slightly soft. The skin will be smooth and glossy. The aroma will be fragrant.
Peppers – Look for a firm body with thick walls, smooth skin, and a bright and shiny color. They can be any size, but the longer bell peppers stay on the plant, the more sweet they become and the greater their Vitamin C content.
Beets – Look for small to medium-size roots. Beets can be harvested at any time, but the larger ones will often be tougher and woody. Beets should have smooth, firm flesh, show a rich color, and have healthy green leaves (not wilted).
Potatoes – Potatoes should have a firm body and be heavy for size, without any black or soft spots, sprouts, wrinkles, or greenish tinge. If you’re growing potatoes, harvest the first delectable little potatoes when plants have just bloomed. For more-mature potatoes, which will be the best keepers, wait until the foliage has died down.