How to Harvest
Vegetables are harvested at different times and in many different ways. Certain vegetables such as peas, beans, cucumber, and zucchini need to be harvested on a regular basis to keep the plant producing. Some plants only produce one item, and you'll want to harvest it at the peak of ripeness. Others will keep producing a crop over several weeks, and others still will produce second crops but in smaller sizes.
Salad stuff such as lettuce, spinach, Swiss chard, oriental greens, and salad greens can be harvested by individually cutting baby leaves or mature plants. For baby greens, which are wonderful in salads, cut the plants when they are two to three inches high. If the roots are not disturbed they will grow back. You can usually get two cuttings before they stop producing or start tasting bitter. For a mature plant, check the seed packet to see how long it is supposed to take to mature. Most plants do not grow much higher than twelve to sixteen inches. A mature plant can be cut off at the base of the plant, or individual leaves can be cut as well (most common in Swiss chard). The plant will grow again if the root is not disturbed, usually producing a smaller head. Pick a leaf from a salad vegetable and test it to see if it has a sweet fresh taste. If it does, the plant is ready for your dinner plate. A bitter taste to the leaves is a sign that the plant is finished. Let the plant flower so you can collect the seeds, or pull it out and plant something else in its spot. These vegetables do not store well so they are best eaten fresh.
To keep lettuce fresh longer, moisten a clean kitchen towel and wrap it around the vegetable. Place this into a plastic bag and put it in the refrigerator. Do not seal the bag, as it will keep better with air circulation. Stored this way, the lettuce will keep for up to two weeks.
Brassicas, which include your cabbage, broccoli, and cauliflower, are plants that usually produce one good-sized head. Some will produce smaller heads once the main one has been harvested. These vegetables can be harvested once the head reaches approximately four to eight inches in diameter. You'll want your cabbages to have a nice firm head, and this takes precedence over size; they can be harvested when small or left longer in the garden until they get larger. Once the head begins to split you know the cabbage is getting old. After the main cabbage is cut from the plant, smaller heads will form if the plant is left in the ground.
You want to harvest broccoli when the head is a bright green color and still firm — this is also the best time to freeze your broccoli for later use. Broccoli will be less flavorful once it starts to open and begins to flower. This vegetable will also produce side shoots off the main stem that are considerably smaller in size. Cut them regularly as they will go to flower quickly. Cauliflower will produce only one head, so make sure it is filled out and firm before harvesting it.
Peas and beans are best picked early as they are usually sweeter and more tender when small. You want the pea pods to be full and for the pod to be easily opened or sweet tasting if the pod is edible. Once the peas get older, the pod becomes wrinkly and the peas taste bitter and starchy. It is easy to miss a few pods when you are picking them, but it's fine to leave these old pods on the vine for harvesting later; they have value since their seeds that can be planted next year. Once your peas are ready for harvesting, make sure you do so every few days or the plant will stop producing. This is true for beans as well. A fresh green bean is best picked when it is slender and about three to four inches long. Beans become stringy and less sweet as the get older, so pick on the young side if you are freezing or canning your peas and beans.
Before storing beets, carrots, rutabagas, and other root vegetables, make sure the leafy green tops are removed. Tops that are not removed will quickly deplete the nutrients found in the root vegetable. Leave an inch or so of stem so the peel of the vegetable is not broken.
Zucchini needs to be harvested regularly, starting when the squash is four to eight inches long. Tiny zucchini are a delicacy for many chefs since they are tender and taste best when small. They can grow several inches overnight, so check on them every few days. If you happen to miss one, and it is a foot long or more when you find it, harvest it anyway so that the plant will continue to produce. The larger zucchini can be used for a stuffed zucchini recipe or to bake zucchini bread. For canning, choose them on the smaller size as they will be tastier. For winter squash it is best to leave the fruit on the vine as long as you can. A quick test to see if they are ready to be harvested is pricking the skin with your fingernail. If it leaves an indentation it is not ready. If it does not leave a mark then the skin is hard and the fruit can be harvested.
Growing storage potatoes
The advantage to growing root crops is you don't have to eat them as soon as they mature; root veggies are plants that can be left in the ground. They will just grow bigger as they mature, and most will retain their flavor. If you are planning to can or freeze your root vegetables, choose the smallest items for less work later when you will be cutting them into pieces. Carrots, beets, rutabaga, and potatoes can be harvested as small as you want them to be. Pulling these smaller root vegetables, such as baby carrots or beets, makes room for the other plants to grow larger. For new potatoes, dig with your hands around the base of the plant and pull out the ones you can feel. This way the plant is left to produce more potatoes.
Heat loving veggies such as tomatoes, peppers, eggplants, cucumbers, and corn all have specific signals that tell you if they are ready for picking. The tomato indicator is easy to pick out as it starts out a green color and turns red, orange, yellow, or black, depending on the variety you are growing, as it ripens. If left on the vine too long, the tomato will become soft, mushy, and fall to the ground. Tomatoes can easily be canned or frozen for use all winter long. The pepper can be harvested at pretty much any size, but is usually best when it is three inches or so in diameter. Peppers also start out as green and are very often harvested at this stage, however if they are left on the plant they will turn red, orange, or yellow depending on the variety. You have to be patient since this color change may not happen until several weeks after the green pepper has reached full size.
You want your eggplant to be firm and have a shiny skin before harvesting. The fruit is getting old once the color becomes dull. You can harvest cucumbers pretty much at any size depending on the varieties you have planted. Pick the English variety once they are about a foot long and at approximately two inches in diameter. The peeling varieties are best harvested at about eight inches, before they become too big. If a cucumber gets too large it will become seedy and bitter tasting, so choose smaller ones for canning or pickling. All these heat-loving vegetables like tomatoes, peppers, eggplant, and cucumbers will keep producing over several weeks if you continue to harvest the fruit.
The exception to this is corn; each stalk will produce one or two cobs and no more. You want the cob to be filled out and firm before you harvest corn. Gently pull away some of the husk and see if the kernels are bright yellow (some varieties are white or a mix of yellow and white). If they look fully formed and are a good color, gently prick the kernels with your fingernail; they are ready to be harvested if a milky liquid shoots out.