Penelitian ini bertujuan untuk mengetahui (1) variasi lama dekomposisi limbah kulit buah kakao dengan penambahan effective microorganism 4 sebagai pupuk organik mengakibatkan perbedaan pertumbuhan tanaman gumitir (Tagetes erecta L.),(2) variasi lama dekomposisi limbah kulit buah kakao dengan penambahan effective microorganism 4 sebagai pupuk organik yang paling baik mengakibatkan perbedaan pertumbuhan tanaman gumitir (Tagetes erecta L.). Jenis penelitian ini adalah penelitian eksperimen sungguhan dengan Rancangan Acak Lengkap (RAL). Sampel yang digunakan dalam penelitian ini sebanyak 40 sampel bibit tanaman gumitir. Jumlah perlakuan terdiri dari 4 perlakuan (0 minggu, 2 minggu, 4 minggu, dan 6 minggu) yang masing - masing perlakuan diulang sebanyak 10 kali. Data yang diperoleh dianalisis menggunakan uji Anova One Way, dan dilanjutkan dengan uji Least Significant Difference (LSD) pada taraf signifikansi 5 %. Hasil penelitian ini menunjukkan bahwa (1) variasi lama dekomposisi limbah kulit buah kakao dengan penambahan effective microorganism 4 sebagai pupuk organik dapat mengakibatkan perbedaan pertumbuhan tanaman gumitir (Tagetes erecta L.) dengan presentase kenaikan berat kering dari lama dekomposisi limbah kulit buah kakao 0 minggu ke 6 minggu 54,43 %, (2) variasi lama dekomposisi limbah kulit buah kakao dengan penambahan effective microorganism 4 yang paling baik dapat mengakibatkan perbedaan pertumbuhan tanaman gumitir (Tagetes erecta L.) yaitu dengan lama dekomposisi 6 minggu dengan rerata berat kering 4,28 gr.Kata Kunci : kulit buah kakao, tanaman gumitir The purpose of this research was to know (1) the variation in decomposition duration of cocoa fruit peel waste with the effective microorganism 4 addition as organic fertilizer resulted in differences growth of marigold plants (Tagetes erecta L.), (2) the variation in decomposition duration of cocoa fruit peel waste with the effective microorganism 4 addition as the best organic fertilizer resulted in differences growth of marigold plants (Tagetes erecta L.). Type of this research was real experimental with Completely Randomized Design (CRD). The samples used in this research were 40 samples of marigold seedlings. The number of treatments consisted of 4 treatments namely 0 weeks, 2 weeks, 4 weeks, and 6 weeks, each of which was repeated 10 times. The data obtained were analyzed by using the One Way Anova test, and obtained by the Least Significant Difference (LSD) test at the 5% significance level. The results of this research showed facts (1) the variation in decomposition duration of cocoa fruit peel with the effective microorganism 4 addition as organic fertilizer can make different growth of marigold plants (Tagetes erecta L.) with a percentage increase in dry weight from the decomposition of cocoa fruit peel waste 0 weeks to 6 weeks 54.43 %, (2) the variation in decomposition duration of cocoa fruit peel waste with the effective microorganism 4 addition as the best organic fertilizer can lead to the best difference in growth of marigold plants (Tagetes erecta L.) in this research, namely 6 weeks decomposition with a mean dry weight is 4.28 gr.keyword : cocoa fruit peel, marigold plant