When Is the Best Time to Plant Bitter Melon? A Detailed Guide to the Latest Planting Times
Bitter melon is generally planted in March. Some growers first raise seedlings in a greenhouse or polytunnel and then transplant them, so sowing can be brought forward to February. In northern China, seeds are sown and seedlings raised in a greenhouse or polytunnel from late March to early April, with transplanting in early May; in the Yangtze River basin, sowing takes place in mid-March and transplanting in mid-April; in southern China, spring cultivation is sown from January to March, summer cultivation from April to May, and autumn cultivation from July to August. If protective facilities are used, it can also be grown in winter.
The planting time of bitter melon is determined by its growing environment, especially the effect of temperature. Below, the editor will introduce the environmental requirements for growing bitter melon!
Soil Requirements
For container growing, use garden soil mixed with an appropriate amount of lime, decomposed pig manure, superphosphate, plant ash and so on. It can be sown and grown directly in a pot, or seedlings can be transplanted into pots, with thin bamboo poles set up as a trellis for the vines to climb. In courtyards, it is often planted beside a sunny trellis, generally with a plant spacing of 40 to 50 cm. Work in fertile, nutrient-rich soil, mounded 2 to 3 cm above ground level, and keep the soil consistently moist.
Temperature Requirements
Bitter melon has different temperature requirements at different stages of development. The optimum temperature for seed germination is 30°C to 35°C; the optimum temperature for seedling growth is 20°C to 25°C, with growth slowing below 15°C and poor growth below 10°C; the optimum temperature for flowering and fruiting is 20°C to 30°C, and at 25°C to 30°C the fruit set rate is high and the fruit develops rapidly; in the later growth stage, it can still set fruit normally when the night temperature is 10°C and the daytime temperature is 15°C to 20°C.
Light Conditions
Bitter melon is not strict about day length, but insufficient light during the seedling stage reduces its cold resistance and disease resistance, and the stems and leaves tend to grow leggy. During the flowering and fruiting stage, ample light favors stem and leaf growth and a higher fruit set rate, and the fruit also develops faster.
Water and Fertilizer Management
Bitter melon should be given a sufficient supply of water, especially during the flowering and fruiting stage, when it needs even more water; never let it go short of water or stay waterlogged for long periods. Bitter melon is highly tolerant of fertilizer but sensitive to waterlogging, so choose a well-drained, deep sandy loam or clay loam for cultivation. Base fertilizer should mainly be decomposed organic fertilizer, and top dressing should mainly be decomposed human and animal manure and urine, applied once a week. Fertilizer for seedlings should be applied lightly; once the flowering and fruiting stage begins, the concentration can be increased, and after the peak fruiting period, apply 1 to 2 additional applications of potassium fertilizer or compound fertilizer to extend the flowering and fruiting period.