By JAMES TABABA
March is the start of summer in the Philippines. Here are five crops that can be planted this month.
Cowpea (Vigna unguiculata)
Cowpea, or paayap, is a leguminous vine planted mainly for its immature pods and seeds, eaten raw or mixed in dishes. The crop residue after harvest is given to feed farm animals because it is a good source of protein. Sometimes, it is planted together with corn to maximize production in the area by having two cash crops simultaneously. Instead of building trellises for viny cowpea, the stalks of corn will serve as trellises for them to cling to. Furthermore, planting cowpeas in the spaces between the corn serves as living mulches to prevent the growth of weeds. After harvesting, the leaves and stalks of both plants can be used as fodder or silage for cattle, goats, and sheep. These two crops have different peak periods of growth, so they compete less in resources. Also, cowpea is a legume that can increase the available nitrogen in the soil through biological nitrogen fixation, making it a good companion crop.
Cowpeas can be planted throughout the whole year. It grows best in well-drained, fertile, and sandy clay loam soil types with a pH of 5.5 to 6.5. It is adapted to temperatures ranging from 20 ℃ - 35℃. It can withstand drought once established but cannot grow well in flooded conditions.
Land can be manually tilled using a hoe or plowed and harrowed using a tractor. After making the soil loose and friable, create furrows with a distance of 50 cm between rows. Sow 2-3 seeds per hill with a depth of 2.5 to 5 cm and 20 cm apart. Some of the seeds may fail to germinate, so replant missing hills 10-15 days after sowing. Remove excess seedlings two weeks after planting, leaving only two plants per hill.
Depending on the soil fertility, nitrogen fertilizer may not be necessary because excess nitrogen can promote excessive vegetative growth that may delay the plant's maturity. Without soil testing, a rate of 4 bags of complete fertilizer (14-14-14), one bag of urea (46-0-0), and one bag of muriate of potash (0-0-60) per hectare is recommended to be applied 14 days after transplanting.
Irrigate the soil thoroughly weekly. Remove weeds to minimize competition for nutrients and water.
Bush-type cowpeas do not need a trellis. However, viny cowpeas can be easily managed if trellises are constructed.
If cowpeas are intended to be eaten as a vegetable, it is harvested 60 – 75 days after transplanting or 12 – 17 days after flowering when the pods are still tender. a day after flowering. Cowpeas can be harvested every 3 – 5 days. For seed production, the pods are harvested when they turn brown.
Mustard (Brassica juncea)
Mustard or mustasa is a pungent, leafy vegetable. It can be eaten raw, pickled, brined, or cooked in soup and stews.
Mustard can be grown any season. However, it prefers cool temperatures from November to March. It grows well in well-drained, fertile, loam soil with a pH of 5.5-6.5.
Plow and harrow the land twice to achieve the desired soil structure. During this process, compost can be added as a basal fertilizer.
Mustard seeds can be directly sown to the ground or transplanted as a seedling. If grown in a seed bed, transplant the seedlings 15 days after sowing. Plant the seedlings 30 cm between hills and 60 cm between rows. Water regularly since mustard has a shallow root system.
The fresh leaves are ready to be harvested 25-30 days after transplanting. Harvesting is usually done early morning or late in the afternoon to avoid wilting.
Watermelon (Citrullus vulgaris)
Watermelon, commonly known as pakwan, is a crawling vine planted for its sweet, juicy, round fruit. Watermelon is often eaten raw or can be made into a beverage. It is abundant and a popular refreshment during the summer season.
The usual planting month for watermelon is October to January. However, planting can be done as early as September and as late as March to produce off-season fruits sold at higher market prices.
Watermelons grow well in well-drained, fertile, sandy loam soil with a pH of 5.0 – 6.8. It prefers to grow in dry weather conditions with a temperature of 25℃ - 30℃, but the ideal temperature where it produces the best fruit is 25℃.
Land must be plowed and harrowed two to three times to control weeds and attain the preferred soil structure. Watermelon needs good soil aeration for it to grow well, that is why it is important to prepare the land properly.
Apply 20 bags of ammonium phosphate (16-20-0), eight bags of ammonium phosphate (21-0-0), four bags of ammonium sulfate (0-0-60), and organic matter per hectare as basal fertilizer before sowing the seeds. Dissolve four tablespoons of urea in 15 liters of water. Then side dress 170 ml of the solution on each hill three weeks after transplanting. At the 5th week after transplanting, dissolve four tablespoons of muriate of potash (0-0-60) in 15 liters of water and side dress 170 ml to each hill.
Watermelon seeds are planted directly into the soil. Sow 3-4 seeds in each hill, 100 cm apart and 200 cm between rows. After 3-4 leaves emerge, retain only one plant per hill.
Irrigation is important in watermelon production. Do not let the soil get too dry. Apply irrigation when necessary.
Harvest fruits 80-90 days after transplanting or 35 to 40 days after pollination. Maturity for harvest can be done using the tapping method. The tapping method is done by tapping the fruit lightly. The watermelon fruit is ready for harvest if it makes a dull hollow sound.
Peanut (Arachis hypogaea)
Peanut or mani is a ground cover leguminous plant. It is primarily grown for its nuts that can be eaten boiled or roasted, made into peanut butter, or as an ingredient in several Filipino dishes.
Peanuts grow well in well-drained, loose, friable, and sandy loam soil with a pH ranging from 5.8 – 6.5. They grow in almost all Philippine climatic conditions and can be cultivated in any season with adequate irrigation. However, peanuts produce higher yields in dry months from October to March.
For the best growing condition, plow and harrow the field 2-3 times to remove the weeds and achieve the desirable soil structure. Plant one shelled peanut seed per hill at a distance of 5-10 cm during the dry season and 10-15 cm during the wet season.
In the absence of soil analysis, the recommendation of NPK is 30-30-30 per hectare. Before planting, four bags per hectare of complete fertilizer may be applied on furrows as basal fertilizer. Then side dress 2 to 6 bags of calcium nitrate 25 to 30 days after planting to minimize the occurrence of empty peanut pods.
Weeding must be done regularly because peanuts are slow growers and cannot compete with weeds. Even though peanuts are relatively drought tolerant, it needs sufficient water during their pod-developing stage. It is recommended to water lightly but frequently.
Peanuts are harvested 90-140 days after transplanting. Harvesting is done by passing a plow on the field before completely uprooting the plants. The visual signs of peanut maturity include gradual withering and yellowing of leaves, hardness of most pods, having 70-80% prominent pod veins, and the seed kernels being plump and full.
Kangkong (Ipomoea sp.)
Kankong, also called swamp cabbage, is a leafy vegetable known for being easy to plant and propagate. The young kangkong tops are commonly added to the dish sinigang.
There are two classifications of kangkong depending on its preferred growing environment. The aquatic kangkong (Ipomoea aquatica) prefers to grow in swampy or flooded conditions. It grows about 10 meters in length, and its leaves are broad and dull-pointed. In comparison, the upland kangkong (Ipomoea reptans) grows in dry or moist soil. It is usually planted during the dry season of the year. Upland kangkong leaves are narrow and pointed.
Kangkong, given that there is an abundant source of water, can be grown in any season and anywhere. It is propagated either by cuttings or seeds. Kangkong seeds or stems are planted at a distance of 30 cm between rows and 30 cm between hills.
To boost the growth, 100 grams of complete fertilizer (14-14-14) can be broadcasted seven days, sowing every 2 meters of the planting bed, followed by 50g of the same fertilizer on the 14th day after sowing. Regular weeding and irrigation are necessary for it to grow optimally.
Kangkong tops or shoots can be harvested three to four weeks after transplanting.
Production guides are available for download on the Department of Agriculture Bureau of Plant Industry website.