Farmers in the upland and mid-elevation areas of the country used to be the only successful growers of the highly nutritious high-value vegetables brassicas or crucifers. But the development, production and commercial distribution of heat-tolerant, lowland-adaptable hybrid varieties of cabbage, cauliflower, broccoli, Chinese cabbage, and kai-lan by progressive vegetable seed companies have enabled lowland farmers to grow these crops in their areas with nearly the same level of, if not at par with, the profitability that their highland counterparts attain.
Cabbage, one of the oldest of the brassica vegetables, is the ancestor of cauliflower and broccoli. Locally the most widely grown crucifer, cabbage is now a thriving commercial crop in sandy, sandy-loam, clay loam or silty loam soils in sea-level places in Northern, Central and Southern Luzon as well as in the Visayas and Mindanao. Most of this crop’s growers plant hybrid varieties of the Condor brand-Gladiator, Commando and Grand KK Cross, and Green Stream and Green Helmet. These heat-tolerant varieties produce highly marketable heads that are semi-flat, semi-conical or round.
Thorough land preparation is essential in brassica production. Alternately plow and harrow the field at least twice to pulverize the soil well, then make beds or plots at least 30 centimeters high and 1 meter wide. Make the distance between beds 25 cm to 45 cm. For farmers equipped for furrow irrigation, make beds 30 cm wide, while for those who water by hand, bed width should be up to 1 m.
Sow seeds in seedbeds prepared with fine soil, compost, dried chicken manure and 1 kilo of urea (46-0-0) fertilizer for every can of seed to be sown. Processed organic fertilizer and urea may also be used. After the seeds germinate, water the seedbed once a day for the first three days with a starter solution of one tablespoon of urea in a gallon of water or use Peters Water-Soluble Fertilizer Blossom Booster (9-45-15) as starter solution, mixing one scoop of this with 16 liters of water.
To protect the seedlings from too much heat during the dry season and excessive rain during the wet season, build a temporary roof over the seedling bed. Gradually remove the roofing materials as the seedlings grow and let the young plants undergo a hardening process 7-10 days before transplanting by exposing the seedlings to full sunlight.
Many farmers now apply a new technology in seedling production by using commercially available plastic seedling trays filled with Klasmann Peat-based Substrate, a specially formulated medium that enhances seed germination and seedling survival and vigor. The substrate contains peat moss, in addition to nutrients and trace elements needed by plants.
Transplant seedlings two to three weeks after sowing. Water the seedbeds or seedling trays, gently uproot the seedlings, and plant these out at 40 x 60 cm spacing to produce bigger and heavier-sized heads.
Apply manure or compost and 14-14-14 as basal fertilizer at the rate of 10 grams per hill. Two weeks after transplanting (WAT), apply urea at 10 g-15 g per plant and sidedress with the same amount 15 days after the first sidedressing. Drenching the beds with a calcium nitrate solution once every two WAT can also be done, then fertilize each plant with 10 g of 16-20-0 later.
Another option is to just sidedress the crop at 1 WAT with a two-to-one or 50-50 mixture of 14-14-14 and 46-0-0, applying one tablespoonful per plant. The next fertilizer application is three weeks later with a 16-20-0 and urea mixture applied at three tablespoonfuls per plant.
You may also spray the plants with Nor-dox, an organic copper fungicide with bactericidal action that can be mixed with fertilizer. Irrigate the field or water plots before and after transplanting. Mulch with rice straw or plastic film to prevent weed growth and conserve soil moisture.
Cultivation, Weeding and Watering
Cultivate and water the plants alternately before the start of the heading stage. Weed around the plants when these are about 15 cm to 20 cm tall. Another way to weed cabbage plots is by cultivating the space between the rows and hills. Do shallow cultivation to prevent injuring the plants’ roots. The first weeding should be done at 1 WAT, with the frequency of succeeding weeding operations depending upon weed growth.
Always practice clean culture. Irrigate the plots by hand-watering or by furrow irrigation. Provide adequate water immediately after sowing, during germination, after transplanting, and on a weekly basis afterwards.
Pest and Disease Management
Pests of cabbage and other brassicas are the Diamondback Moth (Plutella xylo-stella L.), whose young light green colored larvae first feed on leaves as miners, then progressively make small holes on the leaves; the Common Cutworm (Spodoptera litura) that feed on young and mature leaves, making large holes on leaf blades; the Cabbage Moth (Croc-cidolomia binotalis), whose larvae feed on the leaves, especially the growing points or buds, and bore into the forming heads; and Aphids, soft-bodied insects that form colonies on young leaves and the underside of older ones.
Other pests are the Cabbage Looper, Cabbage Webworm, and Flea Beetle.
Control these pests by spraying the plants with hot pepper and detergent solution, an organic pesticide now commonly used by many farmers.
Diseases of cabbage are Damping Off, characterized by the wilting of seedlings just after germination because of the drying out of the base of their stems, which can be prevented by avoiding over-watering; Head Rot caused by fungi in the soil that attack the plants before head formation and maturity, causing these to start decaying at the base of non-wrapper leaves: Anthracnose of Pepper, whose symptoms are small but rapidly expanding sunken lesions that may appear in concentric rings; and Cercospora Leaf Spot, early symptoms of which are small, circular, water-soaked spots on leaves that later enlarge up to 1 cm or more in diameter. Typical lesions are brown with small to large light-gray centers and dark brown margins, with several spots coalescing and causing the entire leaf to turn yellow.
To control, remove all affected plants or plant parts and bury or burn these. Spray with Nordox and irrigate the field or water the plots regularly to keep soil temperature low.
Depending on the variety grown, cabbage heads are ready for harvesting 55-60 days after transplanting (DAT), when the heads become firm and compact. Include several wrapper leaves for protection. The heads will split when overmature. Rapid growth due to excess moisture and fertility will also cause splitting. Discard and bury rotting heads or place in compost pits.
author: Antonio A. Rodriguez, Agriculture Magazine, trc.gov.ph, photo from freedigitalphotos.net