Watermelon Cultivation in India

Watermelon cultivation can be done as an inter-crop or as a standalone watermelon farm. Here is the beginner’s guide on watermelon farming. Learn how to grow watermelon, watermelon cultivation practices, varieties, season, pests and watermelon plant diseases etc.

‘Cold watermelon on a hot day is simple….bliss!’

The above statement is as true as it could get since watermelon has 92% water. It is a sweet, edible fruit that has a green rind on the outside and edible red-colored flesh with black-colored seeds on the inside. The color of the flesh varies from pink to red. There are some varieties of watermelon that have yellow flesh. According to botanists, this cool fruit has its origins in the African deserts about five thousand years ago. Some of its wild varieties are still found growing here. They found their way up north through Egypt and people began cultivating it during the Roman Era.

Information on Watermelon Plant

Botanically, watermelon is called Citrullus lanatus and it belongs to Cucurbitaceae family. All the different types of gourds are classified under Cucurbitaceae family. The melons grow on a vine that can reach a length of 3 meters. It is an annual plant, that is, it can only survive in one growing season. The vines are covered with tiny hairs; they are thin and have groves in them. The flowers are yellow-colored. The specialty of this plant is that male and female flowers are produced separately on the same plant. The fruit varies in shape from oblong to spherical. The fleshy fruit is encased in a thick rind while the seeds are encased inside the flesh.

Ideal Conditions for Watermelon Farming

Watermelons need warm climate for growth. It can be grown all through the year in places like Tamil Nadu, Karnataka, Andhra Pradesh, Orissa, West Bengal and Rajasthan. It is however very sensitive to frost. Hence it can be only cultivated after the frost in places like Haryana. Otherwise, these must be grown in greenhouses that have adequate protection from frosts.

Climate for Water Cultivation

Being a warm season crop, the plant requires ample sunshine and dry weather for production of fruits. In case they are grown in places where winter is prevalent, then they must be provided with adequate protection from cold and frost. They are extremely sensitive to the slightest of frost and hence care must be taken to keep the frost away from the crop. 24-27⁰C is ideal for the seed germination and growth of watermelon plants. A cool night would ensure ample development of sugars in the fruit.

Watermelon Seasons in India

In India, since the climate is mostly tropical, all seasons are suitable for watermelon cultivation. However, watermelon is sensitive to cold and frost. Therefore, in parts of the country where winter is severe, watermelons are cultivated after the frost has passed. In places like Tamil Nadu, Maharashtra, Andhra Pradesh, etc. watermelon cultivation is possible almost any time of the year.

Soil for Watermelon Farming

Watermelons grow best in sandy loam soil that drains easily. It also grows well in black soil and sandy soil. However, they must have a good amount of organic content and must not withhold water. Water must easily drain off from the soil else the vines are likely to develop fungal infections.

pH for Watermelon Cultivation

The pH of the soil must be between 6.0 and 7.5. Acidic soil would result in withering away of the seeds. While soil with a neutral pH is preferred, it can also grow well even if the soil is slightly alkaline.

Irrigation for Watermelon Growing

Watermelon is a dry season crop and it must be planted with irrigation. The watermelon beds are irrigated two days prior to sowing and then again 5 days after sowing the seeds. As the plant grows, irrigation is done on a weekly basis. Attention must be paid to water stress at the time of irrigation since it can lead to fruit cracking. While irrigating, water must be restricted to the root zone of the plant. Wetting of vines or other vegetative parts must be avoided especially during flowering or fruiting time as wetting can lead to withering away of the flowers, fruits or even the plant as a whole. In addition, wetting of the vegetative parts can also lead to development of fungal diseases. Moisture must be maintained near the roots so that the plants develop taproot system. As the fruits near maturity, irrigation frequency is reduced and it is completely stopped during the harvesting stage. This helps in developing flavor and sweetness in the fruit.

Crop Rotation with Watermelon

Owing to the risk of developing various diseases, watermelon is grown on the same soil only after a period of 3 years. It is usually rotated with paddy or with vegetables like tomato, chillies, etc.

Watermelon Varieties in India

Watermelons grow from seeds. However, it is advisable to sow the seeds of watermelons bought from trusted place. There are different varieties of watermelon in India yielding a good harvest such as Vandana, Kiran, Sugar Baby, Watermelon Sultan, Improved Shipper, Madhubala, Arjun, etc.

There are a few exotic varieties like Watermelon Hybrid Yellow Doll and Watermelon Hybrid Red Doll from China and Mardi gras, Royal Flush, Dumara, Celebration, Paradise, Sangria, Oasis, Star Bright, Baron, Samos, Celebration, Arriba, etc. from America.

Land Preparation and Planting Watermelon Seeds

The land is ploughed until the soil becomes very fine tilth. The land is then prepared according to the type of sowing to be done. Watermelons are generally seeded directly in the farms. However, in case it has to be protected from frosts, then it is seeded in nurseries or greenhouses and later transplanted into the main field.

It is sowed during the months of February to March in North India and then during November to January in west and North East India. The seeds are sown at a depth of 2-3 cm from the top soil. The spacing method during sowing varies according to the type of sowing being followed.

The method of sowing to be chosen depends on the season and climate.

Solarisation

Solarisation of soil is generally not necessary if watermelon cultivation is being done during dry season. However, solarisation can rid the soil of unwanted moisture content and even pests.

Pollination in Watermelon Farming

This is a very important step in watermelon cultivation. Unlike most other crops, flowers on watermelon plants cannot develop into fruits on their own. As mentioned earlier, male and female flowers grow on the same plant, but, separately. The male flowers are smaller in size and appear first while female flowers are huge and appear later. The female flowers have a small fruit at the base. In case it shrivels, it means there would be no pollination. In nature, bees carry the pollen while hopping from flower to flower gathering nectar. Therefore, setting up an artificial beehive in the watermelon field is a good idea. One hive per acre of watermelon field is more than enough.

Manual pollination is done early morning. For manual pollination the steps to be followed are:

• Pluck the male flowers
• Remove the petals around it
• The stamen of the male flower (which contains pollen) is brushed against the stigma of the female flower (which is at the center). This helps the pollen stick to the female flower

It is said that the initial female flowers give the best fruits. Some farmers pinch out the tip of the branch once the fruits are set. This helps them attain large fruits.

Weed Control in Watermelon Farming

Weeding is needed only in the initial stages of watermelon growth. Being a vine, use of herbicides must be done very carefully else the healthy plants may get affected. The first weeding is done about 25 days after sowing. Subsequently, weeding is done once a month. Once the vines begin to spread, weeding is not necessary as the vines take care of the weeds.

Diseases and Plant Protection in Watermelon Farming

Watermelon is affected by numerous diseases such as aphids, thrips, anthracnose, mildew, wilt, etc.

Downy Mildew

One of the major pest in watermelon cultivation.

Causative Agent

Pseudoperonospora cubensis

Nature of Damage

This disease occurs wherein there are frequent rains and hence a high relative humidity. It also occurs when the moisture content in soil is high. The affected plants have a stunted growth. The fruits produced by such plants do not mature and hence have a poor taste.

Symptoms

• Yellow colored spots appear on the upper surface of leaves which spread upto the veins. It gets restricted at the veins. This gives the leaf a mosaic appearance.
• Owing to the presence of moisture, the corresponding lower surface of the affected leaves have a purplish growth.
• The leaves turn necrotic, yellow and ultimately fall off.

Spread

The pathogens primarily spread through soil and weeds. They also spread through rain water splashes.

Treatment

• While transplanting watermelons ensure that the plants are free of the disease.
• Apply fungicide before and after installing the row cover if any.
• There must be enough air circulation in the crop and the humidity level must be kept in check.
• Excess irrigation must be avoided- drip irrigation would ensure just enough water in the soil.
• The field must be constantly monitored.

Powdery Mildew

Causative Agent

Sphaerotheca fuliginea

Nature of Damage

The pathogen mainly affects the upper foliage and growing younger parts. The diseased plants defoliate prematurely and die. In case fruits mature, they are deformed.

Symptoms

• Powdery, whitish, superficial growth on the growing parts, stems and foliage. The growth covers the entire area superficially.
• Diseased areas turn brown and dry.
• Fruits remain underdeveloped.

Spread

The fungus is found in dormant buds and parts of plants. It spreads through the infected plant debris and also through conidia by means of wind.

Treatment

• Ensure proper air circulation in the farm
• Aerate the soil before sowing
• Monitor the leaves constantly for appearance of superficial powdery white growth.
• Apply fungicide regularly.

Anthracnose

Another major disease in watermelon cultivation in India.

Causative Agent

Colletotrichum orbiculare

Nature of Damage

The fungus needs an optimum temperature of 30⁰C with high levels of humidity for 24 hours. It produces a thin film of water on the leaves.

Symptoms

• Begins with a thin film of water on the leaves
• The lesions gradually turn into yellow, dark brown and black irregular spots.
• Stem lesion girdle the stem.
• Vines wilt away.
• Fruits produce circular, sunken cankers that maybe about 6mm deep. This is the most diagnostic symptom of the disease.
• The center of the lesion which is the black in color is covered with a mass of spores (salmon colored) that is gelatinous in nature. This happens in presence of moisture.

Spread

The fungus typically spreads from the debris residue of previous crop.

Treatment

It is hard to control the disease. One way to deal with it is to treat the affected plants with neem oil and crop rotation.

Alternaria Leaf Spot

Causative Agent

Alternaria cucumerina

Nature of Damage

Caused by fungus the disease is favored when the weather is wet for a long period of time.

Symptoms

• Spots first appear on the topmost portion of the plant.
• The older leaves have broad spots on them that vary in shape from round to irregular.

Spread

The fungus mainly spread through soil and plant debris. However, it can also spread through rain.

Treatment

Crop rotation and burning the debris after harvests are some of the ways to manage the disease. If detected during cultivation, then spraying chemicals like mancozeb (0.2%) or copper hydroxide would help keep the disease in check.

Fusarium Wilt

Causative Agent

Fusarium oxysporum

Nature of Damage

The disease affects the stem and root of the plants leading to loss of crop. It needs a moisture content along with a high temperature in soils.

Symptoms

• Chlorosis of leaves is the first symptom of the disease.
• Leaves wilt from bottom to top progressively.
• The infected stem exhibit a brown discoloration

Spread

It spreads through soil in the form of chlamydospores.

Treatment

Seeds and plants ready for transplantation must be free of infection. The soil must be fumigated before sowing. Using resistant varieties of the seeds would help deal with infection.

Bud Necrosis

Causative Agent

Watermelon Bud Necrosis Virus

Nature of Damage

Caused by viruses, thrips play host to the virus. The population of thrips increases during the hot and dry climate.

Symptoms

• Leaves develop chlorotic rings and mottling
• Plants are stunted in growth
• The ring spots turn brownish black and leaves become brown and distorted.
• Fruit surface have ring spots ta tan, become necrotic and develop lesions.

Spread

Thrips population increase rapidly when the climate is hot and dry thus aiding the spread of disease.

Controlling Diseases

One of the best ways to check the spread of diseases is to check the plants, leaves, soil, weather etc. on weekly basis. Action must be taken when needed such as removing the infected plants, collecting the egg masses, etc.

Harvesting Watermelon

Watermelons are ready for harvest when:

• The tendrils near the stem start drying
• The white colored part of the fruit touching the ground turn yellowish
• A thudding sound is produced when the melons are thumped (a dense sound is produced from immature fruits).

Fruits only mature when they are attached to the vine. Hence immature fruits must be left untouched. For harvesting ripe fruits, the stem is cut about an inch away from the fruits with the help of a knife. Upon harvesting, the fruits are graded according to their sizes. Then they can be stored at 15⁰C for maximum two weeks. However, they must not be stored with apples or bananas since the latter lose the flavor.

Conclusion

Watermelon farm attracts some pests and diseases but proper farm management can give exceptional profits from watermelon cultivation.

Reference

1. http://vikaspedia.in/agriculture/crop-production/integrated-pest-managment/ipm-for-fruit-crops/ipm-strategies-for-watermelon/watermelon-crop-stage-wise-ipm
2. http://www.farmer.gov.in/imagedefault/ipm/Watermelon.pdf
3. https://www.omicsonline.org/open-access/growth-and-development-of-watermelon-in-response-to-seasonal-variation-of-rainfall-2332-2594-2-117.php?aid=33705
4. http://agritech.tnau.ac.in/horticulture/horti_vegetables_watermelon.html
5. http://nhb.gov.in/pdf/vegetable/watermelon/wat011.pdf
6. https://www.apnikheti.com/en/pn/agriculture/horticulture/fruit/watermelon
7. http://www.omafra.gov.on.ca/english/crops/facts/10-065.htm
8. http://msue.anr.msu.edu/uploads/files/powdery_mildew.pdf