Melon (Cucumis melon L.) is an important crop for the world economy, and it is one of the most valuable crops in the market. The cultivation of melon in Cambodia is still low due to the unclear use of varieties and the inappropriate cultivation techniques that cannot achieve high yields. This is the reason why this research is conducted. The objectives of this research are: 1. to compare the growth of melon varieties with calcium in Svay Rieng province condition, 2. to study the appropriate level of calcium fertilizer on melon yield in the supplementary stage, and 3. to study the fruit quality of the five melon varieties. This experiment was arranged into Randomized Complete Block Design (RCBD) with 4 replications and 20 treatments equivalent to 80 plots totallyat the Agricultural Station of Svay Rieng University. The results showed that the application of calcium fertilizer and foliar spraying once every 7 days resulted in the highest growth of melon plants. The use of different varieties showed that the melon varieties V4 (Lady Green = 547) and V2 (Lady Gold = 518) received the highest number of seeds. Thus, in summary, comparing the growth of 5 melon cultivars with 4 levels of calcium fertilizer, the results showed that the application of calcium fertilizer and leaf spray every 4 days, every 7 days, made the melon crop. Growth, yield, and fruit quality are excellent. The use of different varieties showed that only the melon varieties V4, V1, and V2 are the best
