Farming Guide for Watermelon Plantation
Family Name : Cucurbitaceae Botanical name: Citrullus Lanatus
Growing watermelons requires lots of space, lots of sun, lots of water and lots of nutrients. They are greedy, rambling vines, like all plants in the cucurbiteae family (e.g. zucchini, squash, pumpkin, cucumbers)
Watermelons are not particularly difficult to grow, but because they are so demanding, watermelons are not a good plant for beginner gardeners. It is also not a good plant for anyone with restricted space, water, or average soils.
In the true tropics the dry season (winter) is the best watermelon growing season. Watermelons do not cope well with extreme heat or the humid, soggy conditions of our wet season/summer. Fungal diseases and bugs will wipe them out in no time. If you live in a cooler climate, then summer is the time to grow watermelons. You do need at least three months of reliably hot, sunny weather to grow and ripen a watermelon. During that time your average daily maximum temperature should be at least about 20-25°C or 70-80F. Warmer is even better.
(There are different watermelon varieties, so if you are at the low end of that, look for a faster maturing variety.) Grow watermelons in full sun. You also need an abundant supply of water and nutrients (good soil).
And you need space. as it is a rambling vine. They like to go wandering and smother everything around them.
Growing watermelons from seed
Watermelons are grown from seed. You may be tempted to use seed out of a melon you bought, but don’t waste your time. It is almost guaranteed to be a hybrid. Hybrid varieties are very special crosses that don’t grow true to type. (You would end up growing what is called pig melons. A melon variety that’s only good for feeding to the pigs)
Buy your seed, and if possible buy an open pollinated heirloom variety. Because then you CAN use your own seed next year. The open pollinated varieties are also hardier. You will find a lot more interesting varieties amongst the heirlooms then you can find in the standard collection of you local gardening centre. Start your watermelon seeds in the ground, right where they are supposed to grow. The soil should be at least 18°C for them to germinate.
Unless you have an extremely short growing season, do NOT start your watermelon seed in a pot or punnet. Do NOT buy watermelon seedlings from a nursery.
Watermelon seed germinates easily and quickly, within a few days. Watermelon plants outgrow the seedling stage very quickly, and they don’t like transplanting. You don’t save much time and you end up with a weaker plant.
Save yourself this totally needless extra work and stick your seeds in the ground, about two cm or an inch deep.
Watermelons need deep, rich, friable soils. To grow watermelons it helps to raise the soil (make mounds or ridges). Raising the soil has several advantages:
A mound or ridge is free draining (melons don’t like wet feet). If you have heavy clay soil, definitely raise the bed.
Mounds are also good if the soil is as poor. Make a mound of good soil with lots of compost in it to grow watermelons. Sometimes you can plant them in what’s left over from a compost pile after using most of the compost.
Organic Watermelon Farm in Kayathar, Tamil Nadu, India. (above)
If you like growing things in neat rows, or if you want to plant a large area, grow watermelons on ridges, like the commercial growers do.
Rows should be about 2 m (6 ft) apart and the plants spaced at 30 cm/a foot apart. (Sow twice as many as you want, and keep the stronger ones.)
Grow watermelons in clumps on a mound, in several different locations in the garden. (Mixing things up helps keeping pests and diseases at bay.) If you want several hills together, keep them about 2 m apart.
The mound should be about one metre square and a foot high. Then plant about ten seeds in it, in three groups of three to four seeds each. The groups are spaced about a foot apart (30 cm).
After a few weeks we see which watermelon plants grow the strongest, and then snip off the weaker ones, leaving only one seedling in each group. (Don’t pull them up, cut them off. Or you disturb the roots of the others.)
Growing watermelon plants
Slugs and other seedling chomping critters like mulch and they like watermelons. Wait until the watermelons have outgrown the most vulnerable stage (where a slug can demolish them within minutes). Then mulch the area well.
Watermelons have very shallow roots and they need lots of moisture. The soil should never dry out, and mulch helps with that.
Mulch also keeps weeds down. Weeding could disturb the shallow roots, so it’s better to not let them grow to start with. Watermelons are VERY hungry plants. If your mulch is something like compost or aged animal manures, all the better. (Like all cucurbits, watermelons can handle fairly raw compost and manures.) Otherwise, feed your watermelons regularly with something like pelleted chook manure or another organic fertiliser. (Ideally you should use a high nitrogen fertiliser in the early stages, but cut back on nitrogen and give them lots of potassium once they flower and fruit.)
When the vines are about two metres long, pinch out the tips. It encourages branching.
As your watermelon vines grow bigger they will start trying to take over more space. If they start to smother other things you can remind them about sticking to their area by gently moving the tips of the vines, so they grow into the right direction.
Watermelon flowering and fruiting
Watermelons grow male and female flowers on the same vine.
The smaller male flowers appear first. The female flowers are much larger (see the photo) and you can’t miss them.
If you don’t see any it could have several reasons: too hot, too cold, not enough water, not enough nutrients… In any way, it means the watermelon plant isn’t happy.
If the plant does produce female flowers but the little fruit at the base of it shrivels up and dies, then the flowers are not getting pollinated.
Watermelon flowers are insect pollinated. If you suspect the insects aren’t doing their job, you can do it yourself, just to be sure.
Hand pollination is best done early in the morning. Pull off a few male flowers and remove the flower petals. Then brush the pollen laden stamen against the stigma in the centre of the female flower, so the pollen sticks to it. Easy.
The first few female flowers on each branch will give you the best fruit.
To grow them as large as possible you can pinch out the tip of the branch after a couple of fruits have set (are starting to swell up).
But this isn’t an essential step. You can also just let them go…
Problems when growing watermelons
The biggest watermelon pest are the leaf eating beetles (they damage the flowers, too) like spotted and striped cucumber beetles, pumpkin beetles with or without dots, whatever you want to call them.
Those orange things…
They all look similar and all do the same: chomp away on your watermelon plants…
However, if they become a real problem it is mainly a sign that your watermelons are stressed.
A healthy watermelon in a balanced environment and in good soil should not attract too many beetles. Also, a watermelon should grow fast enough to cope with a few beetles.
The other main problem with growing watermelons is mildew, a fungus that makes the leaves look as if they were coated with white powder. The fungus thrives in damp, humid conditions.
The best you can do is to avoid getting the leaves wet. If you can’t avoid overhead watering, do it first thing in the morning so they dry quickly. Never wet the leaves in the afternoon or evening.
In the tropics you probably won’t be able to control the beetles or the mildew, once the build up for the wet season starts. And it isn’t worth it anyway… The oppressive heat and the humidity just aren’t good conditions for growing watermelons. Grow something that likes humditiy and wait for the next dry season to grow watermelons again.
Watermelons are mainly cultivated in Maharashtra, Karnataka, Tamil Nadu, Punjab, Rajasthan, Madhya Pradesh, and Uttar Pradesh.
It is a trailing annual vine with stems 15 m or more in length and branched tendrils having yellow flowers bearing globular to oblong fruits loght green to almost black and either solid or with pale green colour or marbled. striped
Name of the variety/Source & its Characteristics
IARI, New Delhi
Mid-season variety, medium sized fruits with average fruit weight 6-8 kg. The rind colour is light green with deep pink-flesh; TSS 11 to 13%. The fruits ripen in 95 days.
IARI, New Delhi.
The fruit slightly small in size, round in shape having bluish black rind and deep pink flesh with small seeds. TSS 11-13%; average weight 3-5 kg. The fruits ripen in 85 days.
Cross between IIHR-20 & Crimson Sweet; mid-season variety; fruits round, rind colour is light green with dark green stripes and flesh crimson colour, TSS 11-13%. Average fruit weight 6-8kg.
The fruits are round to oval with green rind and dull green stripes. The flesh is deep red, very sweet taste with TSS 12-13%. Average fruit weight is 6 kg. It stands well in transport and storage. Resistant to powdery mildew and tolerant to anthracnose disease.
Fruits large in size with dark green rind, average fruit weight 8-9 kg/ha, moderately sweet with TSS 8-9%.
Early maturing variety, Fruits are round and small with red flesh and seeds, average TSS is slightly lower than Shipper variety.
ARS, Durgapura, Rajasthan
A late maturing variety, fruits are round rind is thick and light green in colour, flesh sweet and dark red in colour, good keeping quality, TSS 11%, average fruit weight 6-8 kg, seed with black tip and margin. The fruit ripens in 125 days.
ARS, Durgapura, Rajasthan
A late maturing variety. Rind is green in colour with stripes; flesh yellow in colour and moderately sweet, seeds are large. Average fruit weight 4-5 kg.
Watermelon Hybrid Yellow Doll, Water Melon Hybrid Red Doll.
Arriba, Athens, Carnival, Celebration, Dumara, Fiesta, Jade Star, Mardi Gras, Regency, Royal Flush, Royal Majesty, Royal Sweet, Paradise, Sangria, Oasis, Star Bright, Ferrari, Sunrise, Baron, Matador, Samos.
Season of Planting
The land is brought to fine tilth by giving two crosswise ploughing. In North Indian plains, watermelons are sown in February-March whereas in North eastern and western India best time of sowing is during November to January. In South and Central India, where winter is neither severe nor long, these are grown almost round the year.
Methods of Planting
Before sowing seeds are soaked in luke warm water for 12 hours. The water is drained out and the seeds are kept overnight in a wet gunny bag. This treatment increases the germination percentage. Normally 1.5 – 2 kg of seeds are required for planting one hectare area. Various system of sowing has been adopted depending on the season and system of cultivation.
In this method, furrows are opened at a distance of 2-3 m apart. Sowing is done on either sides of furrows and the vines are allowed to trail on the ground. 3-4 seeds are dibbled at a distance of 60-90 cm along the furrow.
In case of pit method, pits of size 60 x 60 x 60 cm are dug at spacing of 2-3.5 x 0.6-1.2 m and filled with FYM (Farm Yard Manure) and soil in equal proportions. Four seeds per pit are sown and finally two to three healthy vines are retained.
In case of planting in river beds pits of size 30 x 30 x 30 cm are dug at a distance of 1-1.5 m. The pits are filled with equal quantities of soil and FYM. the soil is piled up in the form of a hill and two seeds are planted on each hill.
Watermelons can be grown on well-drained sandy to sandy loam, medium black soils rich in organic matter. Alluvial soil along the river beds is also good for production of watermelons. A pH range of 6.0- 7.0 is considered as optimum.
Watermelon is a warm season crop grown mainly in sub-tropical and hot-arid regions. The crop requires dry weather with abundant sunshine for quality fruit production. Watermelons are susceptible to light frost and are provided with partial protection if grown during winter months. Temperature range of 24-270 C is considered as optimum for the growth of the vines. Cool nights and warm days are ideal for accumulation of sugars in the fruits. The seed germinates best when temperatures are higher than 200 C. High humidity at the time of vegetative growth renders the crop susceptible to various fungal diseases.
Manuring & Fertilization
The fertilizer doses to be applied depend on variety, fertility of soil, climate and season of planting. Generally well decomposed FYM (Farm Yard Manure) (15-20 t/ha) is mixed with the soil during ploughing. The recommended dose of fertilizer to be applied per hectare is 100 kg N, 50 kg P O and 50 kg K O. Half the 2 5 2 N and entire P & K should be applied before planting. The balance N is given 30-35 days after planting. The fertilizer is applied in a ring at 6-7 cm from the base of the stem. It is better to complete all the fertilizer applications just before the fruit set.
For increasing the percentage of female flowers, NAA (100 ppm) is sprayed once at two-leaf stage and
the same is repeated after 6-7 days.
Usually pits, ridges or beds are irrigated a day or two prior to planting of seeds and the next irrigation, preferably light, is given 4 or 5 days after planting of seeds. Subsequently the irrigation is given at weekly intervals.
In spring-summer crop, frequency of irrigation is very important as water stress during fruit development leads to fruit cracking. Mulching of the hills after sowing reduces moisture loss at the time of emergence and prevents crust formation. It is necessary to keep the moisture well maintained at the root zone, to promote rapid taproot development. Application of water should be restricted to the base of the plant or root zone to avoid wetting of the vines or vegetative parts, especially when flowering, fruit set and fruit development are in progress. Frequent wetting of stems, leaves and developing fruits will promote diseases and rotting of fruits. Frequency of irrigation is reduced when the fruits reach near maturity while it is completely stopped at harvesting stage.
Gap Filling and Thinning
Under ideal conditions, the seeds germinate within 8-10 days after sowing. One to two healthy seedlings are retained at each spot while the rest are removed or used for gap filling.
Depending upon the season about 2-3 weeding operations is required. The first weeding should be done 20-25 days after sowing while subsequent weeding are done at an interval of one month. When the vines start spreading, weeding in between the rows, or ridges, becomes unnecessary since vine growth can smother the weeds.
In watermelon, apical shoots are pinched when the vines are 1m while allowing the side shoots to grow. This practice gives significantly higher fruit yield. At the initial stages of fruit setting, malformed, diseased and damaged fruits are removed and only 2-3 fruits per vine are retained. This results in increased fruit size and yield.
Watermelons can be profitably grown in the interspaces of newly planted orchards during the initial years provided there are sufficient irrigation facilities.
The crop is ready for harvest in about 75-100 days after sowing depending upon cultivar and season. For local market harvesting should be done at full maturity while for transporting to distant markets, it is done slightly earlier. Maturity in watermelon can be judged from withering of tendril, change in belly colour or ground spot to yellow and thumping test. The mature fruits on thumping gives dull sound as against metallic sound of unripe fruits. The fruit should be separated from the vines with the help of a knife.
The yield of watermelon varies according to the system of cultivation, variety, season and several other factors. The average fruit yield varies from 20 to 25 t/ha.
Post Harvest Technology
Watermelons are graded according to their size for local market. Distinction among grades is based predominantly on external appearances. However, watermelons should be symmetrical and uniform in appearance. The surface should be waxy and bright in appearance devoid of scars, sunburn, transit abrasions or other surface defects.
The fruits are transported by road in bulk by stacking them on dried grass in trucks.
Watermelons can be stored for 14 days at 15°C. For short-term storage or transit to distant markets (> 7 days), watermelons can be stored at 7.2°C with 85-90% relative humidity. Extended holding at this temperature will induce chilling injury. Many watermelons are still shipped without pre-cooling or refrigeration during transit. These fruit must be utilized for prompt market sales as quality declines rapidly under these conditions.
Watermelons should not be stored with apples and bananas as the ethylene produced during storage from these fruits hastens softening and development of off flavour to watermelons.
Scoop out the seeds from a ripe melon and put them into a wire mesh sieve, then with running water over the seeds rub them gently against the mesh, using it to loosen and remove the stringy fibers. Next place the cleaned seeds in a bowl of water, stir it a few times. Some seeds will float to the top….these are immature or sterile melon seeds, they are hollow and/or light-weight and will float to the top of the water. Skim away these bad seeds and discard them. Stir a few more times and repeat the process until no more sterile seeds float to the the top. Drain the water from the remaining seeds.
Afterwards, line a heavy plate or baking pan with waxed paper, spread the seeds out in a single layer onto the waxed paper and place it in sunny spot to air-dry.
Stir the seeds occasionally during the next few hours to make sure all sides are exposed to fresh air, this facilitates even drying. After a day in the sun bring the seeds into the house where they continue to dry for another week or two, stir them daily so they dry evenly. If you’ve got rainy weather the increased humidity can prolong the drying process another week or so.
Melons have thick seeds so be sure they are thoroughly dry before packing them for storage.