Daniel Gill, Merrill, Thomas A. | 11/22/2005 3:58:06 AM
By Dan Gill
LSU AgCenter Horticulturist
Winter vegetable gardening is tremendously rewarding. The vegetables grown here during the winter are some of the most delicious and nutritious our home gardens can produce.
Many of the vegetables we planted back in the fall are ready to harvest, and it is important to harvest vegetables at the right stage for best results.
To help you make sure you do that, here are a few guidelines for some of the most commonly grown crops:
Root crops are harvested when the root is the proper size. Usually, the top of the root is readily visible at ground level, but it is easy enough to push aside the soil at the base of the leaves to check on the size of the root.
Harvest radishes and carrots when the root is about 1 inch across. Carrots can be left in the ground once they are mature and harvested as needed, and the tops can be used as a parsley substitute. Harvest turnips when they are 2-3 inches in diameter, and rutabagas – a close relative – when they are 4-5 inches in diameter. Beets are best harvested at 2 inches and parsnips at 1½-2 inches. Once harvested and cleaned, root crops can be stored for weeks in the vegetable bin of your refrigerator and used as needed.
Incidentally, to get good production, these plants must be spaced properly in the bed. When the seeds that you plant come up, it is very important to thin the seedlings to a spacing at least as far apart as the width of the mature root. If this is not done, the roots generally will not develop properly.
Broccoli heads are not harvested based on the size of the head. Instead, they are harvested when the largest individual flower buds are about the size of a kitchen match head. Do not allow the heads to remain on the plant so long that some of the buds open into a yellow flowers. In addition, remember that smaller side heads will develop and provide additional harvest after the main head is cut.
Harvesting cauliflower also depends more on the appearance of the head rather than its size. The head should be relatively smooth when you harvest it – very much like the cauliflower you buy in the supermarket. If allowed to stay on the plant too long, the sections of the head will begin to separate and it will lose quality. If you did not blanch your cauliflower by covering the head with the plant’s leaves, it may have a purple, green or yellow tint to it. This does not greatly affect the quality of the head.
Leafy crops such as mustard, spinach, Swiss chard, leaf lettuce, collards and turnip greens should be harvested frequently by breaking off the lowest, largest leaves. This is called cropping, and it provides harvest over an extended period. In the case of mustard and turnip greens, you may also harvest the entire plant when it reaches the desired size, but you will get only one large harvest from the planting. Harvest the entire head of semi-heading varieties of lettuce, such as bibb, buttercrunch and romaine, when the head is fully developed.
Cabbage is ready to harvest when the head is solid and hard. Cabbage is one of the few crops that may be left in the garden after they are ready to harvest, although the heads may split. If you are going to leave fully formed heads in the garden, rotate the entire plant one-half turn to prevent splitting (this slows water uptake by breaking some of the roots).
Snow peas and edible podded peas are productive, delicious and well worth growing. Harvest snow peas when the pods are full size but still quite flat. Edible podded peas, such as "Sugar Snap" peas, should be harvested when the pods are full and round but before the peas inside the pod have fully developed. Both types of peas should be checked daily and harvested frequently.
Bunching onions and shallots can be harvested anytime during the winter when the tops are large enough. Dig up the entire clump and separate off half to three-quarters of the bunch to eat. Then replant the rest to continue to grow and divide for future harvesting.
Cold Protection for Winter Vegetables
Although winter vegetables generally are hardy, December plantings may need to be protected from hard freezes – as will certain vegetables near or at harvest stage.
If temperatures below 32 degrees Fahrenheit are predicted, young seedlings should receive special attention. Completely cover them with a 4- to 6- inch layer of loose mulch, sheets or tarps. The cover may remain over the plants for a few days, but remove it as soon as the freezing episode is over. Plastic covering supported off the plants or floating row coverings such as Reemay also may be used.
Even though the plants are quite hardy, broccoli and cauliflower heads are tender, and the leaves, flowers and pods of peas may be damaged by hard freezes. Rather than trying to provide protection, gardeners should just consider harvesting all mature and nearly mature produce before a major freeze.
Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at www.lsuagcenter.com. A wide range of publications and a variety of other resources are available.