Daniel Gill, Merrill, Thomas A. | 4/19/2005 10:28:58 PM
By Dan Gill
LSU AgCenter Horticulturist
The vegetables we grow here during the cool season are some of the most delicious and nutritious that our home gardens can produce.
Better yet, many of the vegetables we planted in late summer and early fall are ready to harvest – or they will be soon.
Since it’s important to harvest vegetables at the proper stage for best quality, here are a few guidelines for some common cool-season 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, if not, it is easy enough to brush 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 an inch across. Also, be sure to harvest radishes while they are young. On the other hand, 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 and rutabagas (a close relative) when they are 4-5 inches in diameter. Beets are best harvested at 2-3 inches and parsnips at 1½-2 inches.
Incidentally, to get good production, these plants must be spaced properly in the garden. When the seeds that you plant come up, it is very important to thin the seedlings at least as far apart as the width of the mature root in order to get good production. Leaving the seedlings too crowded is a common reason that root crops produce small or misshapen roots.
Moving to another cool-season crop, 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 to produce a yellow flower. Remember that smaller side heads will develop after the main head has been harvested, so leave the plant in place for additional harvest.
Harvesting cauliflower also depends more on the appearance of the head rather than its size. The curds of the head should be relatively smooth – very much like the cauliflower you buy in the supermarket. If allowed to stay on the plant too long, the head will begin to separate and 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 turnips should be harvested frequently by breaking off the lowest, largest leaves (this is called cropping). 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 green shallots can be harvested anytime during the winter when the tops are large enough. Dig up the entire clump and separate half to three-quarters of the bunch. Then replant the rest to continue to grow and divide for future harvesting.
Cold Protection for Winter Vegetables
Although winter vegetables generally are hardy, new plantings may need to be protected from hard freezes – as will certain vegetables at or near harvest stage.
If temperatures below 30 degrees F are predicted, young seedlings should receive special attention. Completely cover them with a 4- to 6-inch layer of loose mulch like leaves or pine straw. The mulch may remain over the plants for a few days, but remove it as soon as the freezing episode is over. Plastic covering supported off of the plants, fabric sheets or floating row coverings also may be used.
Although the plant itself is quite hard, the heads of broccoli and cauliflower are prone to cold injury if temperatures below 30 degrees occur. The leaves, flowers and pods of peas also may be damaged by hard freezes. Rather than trying to provide protection, the gardener should consider harvesting all mature and nearly mature produce before the 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.