In organic agriculture only natural methods of cultivation (fertilization and plant protection) are allowed. The total conventional strawberry production in 2014 was 216 thousand tones on the 53 thousand ha. Organic production was on a very low level with only 5 thousand tones cultivated on 1.3 thousand ha of area. Experiment was carried out in the years2013-2014. One strawberry cultivar Honeyoe was cultivated in two experimental organic farms. In one organic farm EM, as well as in the second only organic practice without effective organisms have been used. Three times of harvest have been organized in every experimental year. In fruits the content of dry matter (by scale method), vitamin C (by spectrophotometric method) as well as polyphenols (by HPLC method) have been determinated. The obtained results were statistically elaborated with post-hoc Tukey test ( =0,05). The obtained results showed that using of effective organisms had significant impact on the caffeic, p-coumaric, quercetin, glucoside-3-O-quercetin and luteolin content in strawberry fruits. The third fruits harvest time was the most effective in case of dry matter, vitamin C, gallic, ellagic, p-coumaric acids as well as some flavonoids (quercetin and its derivates), luteolin, kaempferol and pelargonidine-3,5-di-rutinoside in experimental strawberry fruits.