By ZUBAIR DANIEL
Watermelons are tropical or subtropical plants and need temperatures higher than about 25 °C (77 °F) to thrive. In Nigeria, water-melons grow well both in the rain forest regions and in the dry savannah regions, but foliar diseases are less destructive in the drier zones. This is because it requires warm climate and relatively long growing season.
The temperature of the climate has to be hot in order to avoid poor germination which is why the largest production of the crop comes from the northern part of Nigeria where the suitable climate is found.
Nevertheless, a good crop could be achieved in the southern part with intensive management. Seeds are first sowed in pots, then are transplanted to a well-drained sandy loam with a pH of between 5.5 and 7 and medium nitrogen levels. The vines are grown in raised rows, known as hills. This ensures good drainage and will hold the sun’s heat longer.
In a 5-foot-wide hill space the plants about 2 feet apart. Watering is very important until fruits begin to form. Keep the soil moist but not waterlogged. Water the base in the mornings and avoid wetting the leaves. It is very important to note that dry weather produces the sweetest watermelons. Therefore watermelons are best planted during the dry season i.e. from late October to March.
There are various varieties of water melon species and they vary widely in taste, size, shape, texture and color. Some of the common watermelon varieties are:
- Sugar baby: matures in 75 days, very sweet melons weighing nine pounds, red flesh, short vining plants, good for limited space.
- Crimson sweet: matures in 85 days, this watermelon variety produces 25 pound melons with sweet red flesh, high sugar content, thin rinds, very disease resistant.
- Charleston gray: matures in 85 days, long vigorous vines, light green skin with sweet red flesh, 30 pounds.
- Orangeglo Golden Midget: matures in 90 days, very sweet and crisp, oval-shaped melons average 40 pounds, bright orange flesh with off-white seeds.
- Jubilee: matures in 95 days, 40 pound melons with green stripes and red flesh, very fine texture, grows well in hot weather.
- Green gold
- Ice box
- Sweet beauty
Pest and Diseases
There are very few pests and diseases known to affect watermelon and they include:
- cucumber beetles
- squash vine borer moth
- and root-knot nematodes attack this crop,
During high humidity, the plants are prone to plant diseases, such as:
- Powdery mildew
- Rind necrosis
- Blossom-end rot, etc.
Watermelon performs optimally at a low or moderate rainfall or high sunshine also; sweeter watermelons are produced during the dry season. Generally, there are two main planting periods for watermelon which are; the early planting and late planting.
The early planting period begins late February to first week of March, while the late planting period begins late August to early September. However, Watermelon can be grown almost throughout the year with adequate irrigation system and effective pest and disease control methods.
♦ SITE SELECTION: Before selection of site for planting watermelon there are a few things the farmer needs to put into consideration which include: the slope of the site must be flat and not sloppy, it must be a well-drained sandy loamy soil; stony, clayey and waterlogged soils should not be used. The site for watermelon farm must have enough sunlight. The soil must be fertile with good organic matter content.
♦ LAND PREPARATION: Clear all vegetation cover; prune all trees and shrubs that could obstruct sunlight to reach the watermelon plant. Plant residues should be burnt and could further be used as mulching material. A systemic herbicide such as Glyphosate can be sprayed to control harmful weeds such as spear grass, etc.
Conservation tillage is best especially when the soil is of sandy loamy texture class. But in case the soil texture is clayey, a little ploughing and harrowing may be necessary to facilitate deeper rooting and moisture penetration.
♦ SEED PLANTING: This begins with the farmer having the knowledge of the appropriate variety suited for the available market and the particular production situation because this determines the variety the farmer will harvest. The seeds used for planting come in various sizes and are of different hybrids.
This hybrid seeds can be gotten from local agro-related shops nationwide. It is not advisable to use seeds from previous watermelon fruits because this will produce crops with low yield, reduced sweetness and disease susceptibility.
The price of the seed depends on your location. Generally, 500Grs hybrid watermelon seeds for planting cost between M4, 000 – N7, 000. The seeds are sown on the plots at 2 seeds per stand at a depth of 2.5-3.0cm, using a spacing of 100 cm apart on rows x 175 cm between rows, with 1 m Alley pathways. Watermelon vines require considerable space.
Based on varieties, the order of superiority in vine length, number of leaves per plant, number of branches per plant, weight of fruit and sweetness of fruit is Sugar baby > Charleston gray > Crimson sweet > Green gold > Jubilee > Ice box.
♦ WATERING: For the first few weeks after planting, you need to water the watermelon generously twice in a week, then reduce the watering to just once every two weeks as soon as the vines start sprouting out.
♦ FERTILIZER APPLICATION: fertilizer can be applied when the vine begins to spread or when the flower begins to blossom and the fruits begin to set this will ensure that the plants are getting the energy they need to produce high quality fruits. A granular fertilizer of NPK 10:10:10 or 5:5:5 can be used to fertilize the soil. The appropriate dosage of the fertilizer should be applied to the base of the plant, well distributed and watered. It should not touch the plant to avoid the plant being burnt.
♦ WEEDING: pre-emergence herbicides should be applied prior to or 12 hours before planting to suppress noxious weeds such as spear grass. Shallow mechanical control of weeds with the use of a hoe can be done before the vines start trailing.
♦ PEST AND DISEASE CONTROL: cucumber beetle is the major pest that causes feeding damage to seedling plant and can be controlled with the use of appropriate foliar applied insecticide to avoid complete defoliation.
Disease can be controlled by cultural practices such as crop rotation, mixed cropping, etc. because old crop debris in the soil carry many fungal, bacterial and nematode pathogens. A preventive program that combines the use of cultural practices, genetic resistance, and chemical control as needed usually provides the best results.
♦ HARVESTING: watermelon reaches harvest maturity 75-95day after planting. Cut melons from the vine rather than pulling or breaking off to reduce chances of stem decay. Leave a long stem on the fruit while harvesting. Indication of ripeness includes: change of color of the ground spot from white to rich yellow, hollow sound if hit several times with knuckle (i.e. thumping), dried spiral coil on the stem, etc.
♦ STORAGE: Watermelons cannot store for a long period; but will keep for 2 to 3 weeks at low temperature (11°C to 15°C). Relative humidity should be 85% to 90%; higher humidity may promote stem-end rot. At higher temperatures, watermelons are subject to decay. Watermelons should not be exposed to direct sunlight. Avoid heaping in storageand transporting them with other fruits which emit ethylene such as tomatoes, ripe pears, etc. because watermelons are sensitive to ethylene.
ECONOMIC VIABILITY OF WATERMELON CULTIVATION
- Relatively low capital requirement: one can start up watermelon cultivation with as low as N30, 000 so far as the land is already available. It does not also require huge equipment or expertise which will require huge sum of money. The items used – chemicals, seeds, fertilizers, etc. is also not very expensive.
- High Turnover-: It takes a watermelon seventy five to ninety five days to get to maturity from the planting date. This means you can have up to three sets of harvested watermelon fruits within the year and if your parcel of land is large enough, then you are sure to get huge returns on your investment.
- Ready Market-: there is a comparatively high demand for watermelon in the Nigerian market today. It is one of the popular and most eaten fruits in the country. Most people take it as a snack, for health purposes and as supplements to diet. Watermelon also contains some enzymes that help to fight against cancer causing cells in the body. For this reasons, watermelon has a large ready market.
- Watermelon Is Pest Resistant-: watermelon has resistance to most pests and diseases that usually affect plants. Therefore, you will not need to spend much on adopting expensive pest control measures and chemicals. Thereby ensuring standard rate of return to investment.
- Easy to Start: Watermelon cultivation does not require much technical knowledge to run the farm. As long as you have the land space needed for the farming, you don’t need much of other things to get your watermelon business up and running.
There are limitations towards a complete success in the cultivation of watermelon and they include:
- Changing climatic condition: the greatest challenge which any watermelon farmer would face is the irregular climatic condition in the country due to global warming and the release of greenhouse gases. But with good timing this challenge can be overcome.
- Pests and diseases: diseases such as blossom-end rot, bursting, rind necrosis, etc. could reduce the quality of the watermelon fruit thereby making it unmarketable or edible which in turn causes loss to the farmer. Although this may not be much of a challenge if adequate care is put in place with the use of the right pesticides, fungicides and insecticides.
- Lack of irrigation system: this is the greatest challenge of watermelon farmer especially in the drier regions (i.e. northern part of Nigeria). This could limit the farmers from producing this crop throughout the year.
After harvesting, the final step is transportation from the farm to the wholesaler, retailer or final consumption for sale. To successfully sell your watermelon produce, you have to know who your market is. The main market for your produce include: owner of fruit stores, grocery store owners, restaurants and hotels, pharmaceutical companies that need watermelon extracts as raw material for the production of supplements. An important consideration in successful marketing is to have adequate facilities for transportation of the crop to the market outlets.
Although being an early seller usually results in higher prices, quality and maturity should be of prime importance in marketing watermelons. Synchronizing the local harvest time with time of short fall in supply from the northern part of Nigeria where large scale production is carried out with irrigation is a good way to sell at higher price.