Rhubarb, shallots and horseradish are vegetables that can be easily grown on Long Island, but are not very common in most gardens. All three of these vegetables are grown commercially to a very limited extent on Long Island, and are really not very difficult to grow in a garden area.
This perennial is a member of the buckwheat family and can easily be grown in our well-drained sandy soil. It is often best to plant this in a well-isolated area, away from traffic areas. Often it is best to put rhubarb next to the corner or side of the regular vegetable garden.
Rhubarb can easily tolerate cold winters and dry summers because of the large underground fleshy and somewhat woody rhizomes and fibrous root systems. In general, the crop does not grow very well in hot locations and it will not tolerate poorly drained areas. Often, it is better to plant rhubarb on a slightly raised bed or the better drained area of the garden. The reason for this is the roots and underground rhizomes will suffocate during the heavy rainfall periods of spring, summer or fall.
Prior to planting in the spring, the soil should be well-fertilized and limed. The pH should be approximately 6.2 to 6.5 with fertilizer applied and mixed in. A complete fertilizer, such as a 5-10-5, at about 5 pounds per 100 square feet should be adequate.
Planting is done by using young pieces of crown containing good strong buds. Older crowns should be separated and the outer portions planted. Planting is done after the ground has thawed and can be worked properly.
The crowns are set deep enough so that the top of the crown is covered with about two inches of soil. Crowns are set about two feet apart in rows that are 4 to 6 feet apart.
Clean shallow cultivation should be continued through the growing season so that weeds are kept to a minimum. During the first year, the rhubarb should not be harvested and should only be harvested a short period (no more than two weeks) during the second full growing season. In the third and subsequent seasons, the harvest period can last from six to eight weeks.
Harvesting is done by pulling (not cutting) the leaf blade from the growing plant. Normally this will break off at the junction and produce very little injury to the parent. Stalks should have a good red or pink color at the time of harvest. The leaf blade itself should not be consumed.
Petioles are then washed and can be eaten raw or cooked, steamed or prepared in many different ways. Once a bed has been in production for three or more years, you would be surprised at the amount of rhubarb that can be produced from a small garden area.
A shallot is related to the onion and is used as a dry bulb or as a green young plant in much the same way as onions. The more popular way recently has been to use shallots as a dry bulb.
Shallots are easy to raise in gardens on Long Island because our soils are generally sandy and well drained. Soil preparation consists of proper liming and fertilizing. The pH of the soil should be in the range of 6.2 to 6.5 and a good garden fertilizer program used. The most common fertilizer is about 5 pounds of 5-10-5 per 100 square feet applied prior to planting.
Shallots should be planted as early as possible in the spring to promote vegetative growth before bulbing starts. Cloves of shallots are divided and the seedpiece placed in the soil about three inches apart with rows about 15
inches apart. The shallot will tolerate cool temperatures in the spring and will start growth as soon as the soil temperature starts to increase.
Throughout the growing season, it is very important to maintain a good weed control program, because this crop does not compete at all with our common weeds.
The shallot will grow quite rapidly and produce multiple growing points fairly early in the spring. This growth continues until long days are reached, at which time bulbing will start. At the point of bulbing, the carbohydrate in the leaves will move down into the dividing bulbs producing a cluster very similar to garlic.
Throughout the growing season some of the plants may be removed and the green leaves cut and separated or cut into small pieces to be used in place of green onions. This provides a good delicate flavor to many of our food items. The rest of the plants should be left to reach maturity.
Once the top has dried down, the shallots can be removed from the soil and dried at fairly high temperatures in a well-aerated container. Often a mesh bag, such as an onion bag, is used and hung in a dry place to encourage curing. Once the shallot has dried, it can then be used for cooking or stored for later use.
The keys to good shallot production in a garden is to have a well-drained, properly limed and fertilized soil, good healthy bulbs for planting, good weed control, and good curing after harvest. The dry bulbs will then store very well and last throughout the winter and can be used as needed.
Prior to the 16th century, horseradish probably was grown for medicinal purposes only. It is indigenous to Eastern Europe, but is now found throughout the United States because of its culinary uses.
Horseradish belongs to the mustard family, which also includes many of our common vegetables, such as cabbage, cauliflower, radish, cress, etc.
Horseradish can be planted either in late fall or early spring. The more convenient way would be to put the cuttings out as soon as the soil can be worked in the spring following the application of lime and fertilizer. The pH for this vegetable should be at least 6.2. A complete fertilizer such as garden 5-10-5 should be used at about 5 pounds per 100 square feet.
Cuttings are made from healthy roots, and are generally about six inches long and about one-half inch in diameter. These are placed vertically in the soil with about two or three inches of soil covering the top. The soil should be a sandy well-drained area and fairly free of rocks and certainly free of a hard pan or barrier for the roots to develop.
Weed control is generally very easy to achieve because the horseradish grows rapidly and competes very well with other crops, especially weeds. The major danger is that the horseradish itself will become very prolific and itself become a weed where it is not wanted. In this case frequent pulling, especially of the underground roots, is necessary to keep horseradish away from other crops. Horseradish is infected by very few diseases and only two or three insects. The major insect is cabbage maggot which will cause burrowing into the root.
Harvesting is done in late fall around Thanksgiving or can be delayed until the following spring once the ground has thawed. The crop will overwinter very well in place in the garden as long as the area is well-drained and water does not stand or flood the area during the winter months.
Harvesting is done by digging up the roots and separating the major fleshy roots from the side shoots. The root can then be washed, cleaned and ground for use in cooking preparation of sauces, condiments, etc. The addition of white vinegar to the ground horseradish will prevent spoilage or oxidation. In this way, the horseradish preparation can be kept for weeks or months in a cool refrigerated area.
These vegetables -- shallots, rhubarb and horseradish -- can be grown easily in any of the vegetable gardens on Long Island, and when properly raised will provide enough for normal family use, plus plenty to give away to friends and neighbors.
Prepared by William J. Sanok, Cornell Cooperative Extension - Suffolk County.