Seed rate: 1–3 kg/ha depending on variety and planting distances. 6–8 seeds often
planted together on a mound, then thinned to the best 1 or 2 plants. Epigeal
germination.
: very variable, eg Sugar Baby averages 41g per 1000 seeds, Blackstone
averages 125 g. Seed dressing such as Captan or Thiram is often used to combat
mildews.
Spacing: the mounds are about 2–3.5 m apart. Sometimes planted in rows, thinned
to 1–1.5 m between plants.
Depth: 2–5 cm.
Rotation: should not be grown on the same land more often than every 4–5 years,
nor after another Cucurbit crop, to avoid buildup of soil-borne insects(and fungal
diseases to some extent).
GROWTH CONDITIONS
Day length: watermelon plants are day-neutral.
tapped with the hand and when the tendrils have withered.
Temperature: killed by even a light frost. For good fruit development watermelons
need a long hot sunny period with a mean temperature of more than 20°C. For
proper seed germination the soil temperature should be more than 20°C, and
germination will not happen below about 16°C.
Rainfall: fairly drought resistant. If irrigated, this can be done infrequently as the
deep, extensive root system ensures growth during long dry periods. The plants
tolerate fairly humid conditions, though the fruit quality can suffer and diseases may
also develop faster.
Pests: Cutworms and other soil inhabiting insects can be controlled with poisoned
baits, such as Furadan. Fruit flies can be controlled with insecticide. Other pests
include root-knot nematodes, Cucumber Beetle and aphids, controlled with a
combination of rotation with insecticides.
Diseases: Mildews, both Downy and Powdery, may become serious. Also
combination of resistant varieties and sensible crop rotations. Genetic engineering in
the USA has produced some virus resistance.
YIELD
A good crop of watermelons can produce about 1200 fruits/ha, each fruit on average
weighing about 7–8 kg, varying from 1–2 kg to more than 20 kg. Each vine
produces 1–15 fruits. 75 MT/ha is possible under ideal growing conditions.
The global average yield is about 15 MT/ha. Plant breeders aim to produce
varieties with a larger number of smaller fruits, with tough skins, mainly to facilitate
transport.
The yield of seed is about 200–250 kg/ha.
Seed size
GROWING FOOD – THE FOOD PRODUCTION HANDBOOK 265
Anthracnose, Fusarium Wilt & Watermelon Mosaic Virus, all controlled with a
Growth period: 80 150 days. The fruit is ripe when it gives a dull thud when –