Chinyere Anyanwu
Watermelon, one of the most juicy and nutrient-packed fruits around, is not just in high demand in the country for consumption but is equally creating employment for a good number of people.
The fruit, which has a green exterior with a juicy red interior, is made up of 92 per cent water and is rich in potassium and vitamins C, A, E and B and also contains antioxidants.
Among reasons why watermelon is every fruit lover’s delight are its numerous health benefits, including lowering blood pressure, keeping the body hydrated, cleansing and moisturising the skin, aiding growth of healthy hair, as well as aiding digestion.
Cultivation of watermelon, therefore, is a lucrative and worthwhile venture as the market for it is readily available and it is not capital intensive. On the average, with between N100,000 and N150,000, a sizeable and well-cared-for watermelon farm can yield between N800,000 and N1 million profit. This means that with watermelon cultivation, a good number of people can be taken off the job market.
Below is a helpful guide on watermelon cultivation:
Choice of land for watermelon cultivation
Choosing a suitable location that supports the growth of the fruit is very important. The fruit thrives on a fertile well-drained sandy loamy soil that is rich in organic matter. Watermelon is a heat-loving plant requiring a long and warm growing season of at least 70 to 85 days to produce sweet fruit, depending on the variety.
The site must, therefore, have enough sunlight for optimum growth and fruit yield. Farmers in colder climates can also have considerable success in watermelon cultivation by growing their seeds indoors before taking them out and by planting short-season varieties of the crop.
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Land preparation
Cut down all vegetation, trees, and shrubs that could obstruct sunlight from reaching the watermelon plant. Plant residues should be covered properly with soil or burnt or preserved for use as a mulching material for the watermelon plant.
Forming raised beds is best especially when the soil is of sandy loamy texture. In sites where the soil is clayey or hard, a little ploughing and harrowing may be necessary to loosen the soil and facilitate deeper rooting and create room for better penetration of water.
Treat the soil with chemicals that will destroy disease vectors or pests, which may be present in the soil to feed on the watermelon seed.
Seed varieties and seed planting
There are many varieties of watermelon seeds and they can be got from local seed shops or government agencies. Some of the varieties include black diamond, all sweet, royal sweet, crimson sweet, moon and stars, jubilee and Charleston gray, among others.
It is not advisable to plant seeds from consumed watermelon fruits because this will produce crops having reduced sweetness, high disease susceptibility, and reduced yields. Before planting the seeds, they should be treated with fungicides to protect them from fungal diseases in the soil. Also, seeds should be soaked in warm water for 12 to 15 hours, drained and left in a wet bag overnight. This treatment will boost the germination of the watermelon seeds.
Watermelon seeds should not be planted until soil temperatures are warm enough to ensure rapid germination. Planting too early in the season will delay germination, result in the development of uneven stands, and will increase the likelihood of crop loss.
Plant two – three seeds in a hole one inch deep and cover with loose soil. After germination, thin the crop to one or two stands to reduce competition among the plants. The crop requires a lot of spacing and should be planted 3 – 4ft apart within a row and 6 – 8ft apart between rows. This will give the plant enough space to spread its vines.
Watering
After planting, water the seeds for the first three weeks if there is no rainfall. Watering should be done twice in a week without water-logging the plant. After the seeds have sprouted, reduce the frequency of watering to once every 10 days.
When the vines begin to spread out, you can stop watering all together but ensure there is rainfall at least every two weeks. As the fruit begins to get large, stop watering the plant even if there is no rainfall. This will allow the sugars in the fruit to concentrate and make the flesh to stay crisp, producing better tasting watermelons.
Weed control measures/fertilizer application
Weeds compete with watermelon plant for available space, water, and nutrients. It is important to ensure that the land is weed-free. Weeding should be done mechanically or by the application of herbicides two-three weeks after the seeds have germinated.
Watermelon responds favourably to manure and chemical fertilizers. Feed the plant with well-rotted manure to provide nutrients for growth and yields. If chemical fertilizer is to be used, nitrogen-based fertilizer should be applied two – three weeks after planting, after watermelon seedlings have sprouted.
When the plant begins flowering, reduce the use of nitrogen-based fertilizer and increase the use of phosphorus and potassium-based fertilizer. This will ensure that the plants are getting ample nutrients for the optimal production of high-quality fruit.
Pests and Diseases that attack watermelon
The most common pests that affect watermelons are spider mites and aphids. Spider mites thrive in the hot, dry season and they feed on the plant’s sap causing the vines to defoliate in a short time while aphids are common after cool seasons. Other watermelon pests are beetles, melon worms, leaf miners, melon maggots, thrips and so on.
Spraying Acetamiprid, Deltamethrin, Imidacloprid, Thiamethoxam, Lambda-cyhalothrin or Methomyl, according to the prescribed specification, can control these pests.
The major diseases that affect watermelons are fusarium wilt, downey mildew, powdery mildew, gummy stem blight, anthracnose, mosaic virus, among others.
The following steps can help in curtailing the spread of diseases in watermelon farm: avoid overcrowding the plants; ensure removal old plant residues or bury them completely in the soil; follow a good crop rotation plan with maize plant and other non-cucurbits; ensure the plants are exposed to adequate sunlight and good air circulation; avoid the use of overhead irrigation method; and use chemicals to deter the buildup of diseases.
Harvesting watermelon
Timing is important when it comes to harvesting watermelon. If the fruit is harvested too soon, it won’t be sweet; if harvested late, the fruit may be mushy and unappealing. Below are some of the ways to help in determining when watermelon is ready for harvesting.
The colour guide – when there is a little contrast in colour between the stripes, then it is ripe for harvest.
Secondly, thump the watermelon with the knuckles. If it sounds hollow, then it’s ready for harvest. Check the colour of the spot that was laying on the ground.
If it is white, it means the watermelon is not ready for harvest but a cream or yellow colour on the spot signifies it is ripe for harvest. If the spiral coil near the stem of the watermelon is half-dead, it is nearly ripe or ripe. When brown and dried up, it is ready for harvest.