Gap filling and thinning
Under ideal conditions, the seeds germinate within 8-10 days after sowing. Two to three healthy seedlings are retained at each spot while the rest are removed or used for gap filling.
Manuring
Apply FYM @ 20-25 t/ha as basal dose along with half dose of N (35 kg) and full dose of P2O5 (25 kg) and K2O (25 kg/ha). The remaining dose of N (35 kg) can be applied in two equal split doses at the time of vining and at the time of full blooming. A fertilizer dose of 70:25:25 kg N:P2O5:K2O / ha in several splits is recommended in Onattukara region. The fertilizer dose per pit would be 28:10:10 g N:P2O5:K2O.
Irrigation
Irrigate at three or four days interval during the initial stages of growth. Irrigation should be given on alternate days during flowering and fruiting. When fruits are mature, the frequency of irrigation may be reduced. Application of water should be restricted to the base of the plant or root zone to avoid wetting of the vines or vegetative parts, as it will promote diseases and rotting of fruits. Mulching will also help to reduce moisture loss.
Trailing
For trailing the watermelon, spread dried twigs on the ground.
Hormone application
Spraying NAA @100 ppm at two leaf stage and repeating the same after 6-7 days is effective for increasing the percentage of female flowers.
Pinching
To allow the side shoots to grow, remove apical shoots when the vines are 1m. 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.
Weed control
Conduct 2-3 weeding operations; the first being done at 20-25 days after sowing while subsequent weedings 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.
Intercropping
Watermelons can be profitably intercropped in newly planted orchards during the initial years provided there are sufficient irrigation facilities.