Abstract: Four sweet pepper varieties, two from China and two from Netherlands, were cultivated with organic soil substrate in long summer season and their water requirements were analyzed.Resuls show that the varieties from Netherlands such as “Cadete” and “Maribial” have strong growth and higher yield under higher irrigation; whereas varieties from China such as “Zhongjiao 12” and “Tianza 7” show feeble growth but produce higher yield with medium irrigation. It is noted that the higher the irrigation, the larger the single fruit weight for all the varieties. The Chinese varieties can be harvested earlier and yield more in the proph ase. Sweet pepper production is adversely affected by high temperatures in summer but this situation is reversed as the temperatures fa l back to suitable levels. Higher plant and transpiration lead to ower water-use efficiency by the varieties from Netherlands in comparison to those from China. It is also shown that water requirement of sweet pepper changes with plant variety and time of growth; for instance, in hot summer plants need more water for growth. Netherlands varieties with higher yield and strong growth ability require more irrigation than Chinese varieties and are well adapted to cultivation in summer season.