Grapevine growth and fruiting are affected by covering and potassium fertilization. For two years field study, 2019 and 2020 seasons in a factorial experiment in randomized complete block design were conducted to study the effects of plastic covering and potassium fertilizer sources on Flame Seedless grapevines. Flame Seedless grown in Upper Egypt and harvested between 15^th May to 10^th June. In this time, market of table grape is suffering from over supply. Thus, prices decrease considerably in the market. On other contrary, harvesting early (before mid of May) leads to at least a 50% increase in the total income. In this experiment outdoor grown Flame Seedless grapevines were covered with UV+IR (Ultra violet + Infra-red) type of polyethylene film (PE) after dormex application at first week of January. Phenological phases like bud-burst, flowering, veraison and ripening as well as vegetative growth, yield quality were determined. Using potassin or feldspar plus potassin significantly increased the growth, and significantly improved the vine nutritional status as well as significantly yield components and improved berry quality. Plastic covering significantly enhanced the dates of all phonological phases, especially ripening that was earlier about 17 & 22 days in both studied seasons compared to uncovered ones. Plastic covering has a positive effect on growth aspects, yield and fruit quality. So, it could be concluded that Flame Seedless grape cultivar gave the highest and earliest yield with good berry quality when covering with plastic film and fertilized with feldspar plus potassin as natural sources of potassium.