<![CDATA[This research aims to determine the effect of concentration and interval of application of kepok banana peel liquid organic fertilizer on the growth and best results of kailan plants (Brassica oleracea). The research was carried out from May to July 2023 on land around Sekaran Village, Wonosari, Klaten with an altitude of ± 71 meters above sea level. Completely Randomized Design (CRD) with two treatments, namely the concentration of kepok banana peel POC and the interval for giving kepok banana peel POC. The concentration treatment consists of 4 levels (P0: 0 ml/L water, P1: 150 ml/L water, P2: 250 ml/L water, P3: 350 ml/L water) and spraying intervals I1 (every 3 days) & I2 (every 6 days). There were 8 experimental units with 4 replications where each experimental unit consisted of 3 sample plants so there were 96 plants. Plant height, number of leaves, root volume, fresh plant weight, and plant consumption weight are the observation parameters. The results showed that concentration had a significant effect on plant height. The P0 concentration gave the best results on kailan plant height. Spraying intervals have a significant effect on the number of leaves, root volume, and fresh plant weight. The I2 spraying interval provides the best results for the growth and yield of kailan plants. The best interaction was also produced by the P3I2 treatment (giving kepok banana peel POC 350 ml/L of water with spraying intervals every 6 days). Key-words: Concentration, Interval, Kailan INTISARI Penelitian ini bertujuan untuk mengetahui pengaruh konsentrasi dan interval pemberian pupuk organik cair kulit pisang kepok terhadap pertumbuhan serta hasil terbaik tanaman kailan (Brassica oleracea). Penelitian dilaksanakan pada bulan Mei s/d Juli 2023 di lahan sekitar Desa Sekaran, Wonosari, Klaten dengan ketinggian tempat ± 71 mdpl. Rancangan Acak Lengkap (RAL) dengan dua perlakuan yaitu konsentrasi POC kulit pisang kepok dan interval pemberian POC kulit pisang kepok. Perlakuan konsentrasi terdiri dari 4 taraf (P0: 0 ml/L air, P1: 150 ml/L air, P2: 250 ml/L air, P3: 350 ml/L air) dan interval penyemprotan I1 (3 hari sekali) & I2 (6 hari sekali). Terdapat 8 unit percobaan dengan 4 kali ulangan dimana tiap unit percobaan terdiri dari 3 tanaman sampel sehingga terdapat 96 tanaman. Tinggi tanaman, jumlah daun, volume akar, berat tanaman segar, dan berat konsumsi tanaman menjadi parameter pengamatan. Hasil penelitian menunjukkan bahwa konsentrasi berpengaruh nyata terhadap tinggi tanaman. Konsentrasi P0 memberikan hasil terbaik pada tinggi tanaman kailan. Interval penyemprotan berpengaruh nyata terhadap jumlah daun, volume akar dan berat tanaman segar. Interval penyemprotan I2 memberikan hasil terbaik untuk pertumbuhan dan hasil tanaman kailan. Interaksi terbaik juga dihasilkan oleh perlakuan P3I2 (pemberian POC kulit pisang kepok 350 ml/L air dengan interval penyemprotan 6 hari sekali). Kata kunci: Interval, Kailan, Konsentrasi]]>
