Soil: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.
Climate: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 24-27° 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
20° C. High humidity at the time of vegetative growth renders the crop susceptible to various fungal diseases.
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.
The fertilizer doses to be applied depend on variety, fertility of soil, climate and season of planting. Generally well decomposed FYM (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 P2 O5 and 50 kg K2 O. Half the 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.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.
n 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.
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.