First, the budding period
It takes about 10 days from sowing to the appearance of the first true leaf. The optimum temperature for germination is 28-30℃, below 25℃, the germination period is prolonged, the germination rate is reduced, and when it exceeds 35℃, the germination rate is obviously reduced and the seedlings grow thin. Variable temperature treatment can shorten germination period, improve germination rate and seedling quality.
Second, the seedling stage
From 1 true leaf to 5-6 true leaf, it usually takes about 30 days to develop, which is called the seedling stage or cluster stage of watermelon. During this period, the internodes were short and erect, and the leaves differentiated rapidly, but the leaf growth and leaf area expanded slowly, while the roots and new organs differentiated vigorously. At the top of seedling stage, 8-9 completely differentiated leaflets and 2-3 basal parts of Yuan Ye appeared, and the flowers differentiated.
Third, the vine extension period
The flowering period of female flowers from cluster to fruiting node is the main period of vegetative growth, which marks the end of seedling stage. It takes about 18 days for a plant to bloom from clumping to the first female flower, and then a female flower will bloom every 4 days. In the vine-pulling stage, long vines have long leaves, the internodes are rapidly elongated, the plants change from upright to creeping, and the leaves and leaf areas are rapidly expanded. Generally, a big leaf appears in 4-5 days.
Four. Fruiting period
The fruit-setting period is about 25-40 days from the opening of female flowers to the full maturity of fruits.
Extended data:
Watermelon annual vine; Stems and branches are stout with obvious edges. Tendrils stout, pubescent, petiole thick and densely pilose; The leaf blade is papery, triangular, oval in outline, white and green in color, with short bristles on both sides and heart-shaped at the base of the leaf blade. Monoecious. Both male and female flowers are solitary in leaf axils. Male pedicels 3-4 cm long, densely yellow-brown villous; Calyx tube broadly campanulate.
Corolla yellowish; Stamens nearly free, filaments short, anthers folded. Female flowers: calyx and corolla are the same as male flowers; Ovary ovoid, stigma kidney-shaped. The fruit is large, nearly spherical or oval, fleshy, juicy, with smooth skin and various colors and patterns. Seeds are mostly oval, black and red, with smooth sides, obtuse base, usually slightly arched edges, and in summer.
References:
Baidu encyclopedia-watermelon