ABSTRAKKailan bergizi tinggi, memiliki prospek bagus dan disukai masyarakat. Produksi kailan semakin berkurang sehingga diperlukan upaya untuk meningkatkan produksinya, di antaranya adalah dengan pemupukan. Pemanfaatan pupuk anorganik berperan untuk membantu proses budidaya tanaman, namun perlu diimbangi dengan senyawa organik untuk menjaga kesehatan tanah. Air limbah kolam ikan selama ini belum dimanfaatkan padahal masih memiliki peluang untuk diolah menjadi pupuk dalam bentuk bakteri fotosintesis. Tujuan dari penelitian ini adalah mengkaji pengaruh pupuk urea dan bakteri fotosintesis terhadap komponen pertumbuhan dan produksi tanaman kailan. Rancangan percobaan yang digunakan adalah Rancangan Acak Kelompok (RAK) faktorial. Faktor pertama adalah pupuk urea dan faktor kedua adalah dosis bakteri fotosintesis. Faktor pertama terdiri dari R0= kontrol; R1= 5 g/polibag dan R2= 10 g/polibag. Faktor kedua terdiri dari B0 = 0 ml; B1 =10 ml / 2 liter per polibag dan B2 = 20 ml/2 l per polibag. Setiap perlakuan diulang tiga kali. Interaksi antara perlakuan urea dan bakteri fotosintesis menunjukkan pengaruh yang nyata hanya pada tinggi tanaman kailan. Tanaman kailan paling tinggi diperoleh pada interaksi perlakuan R2B1 dan R2B2, yaitu 20,14 dan 19,53. Tanaman kailan paling rendah terdapat pada perlakuan R0B1 dan R1B1 yaitu sebesar 17,46 dan 17,26. Aplikasi pupuk urea tidak berpengaruh nyata pada variabel pertumbuhan dan produksi tanaman kailan. Aplikasi bakteri fotosintesis berbeda nyata terhadap parameter jumlah daun dan luas daun serta bobot segar akar tanaman kailan. Aplikasi bakteri fotosintesis B2 (20 ml) memberikan jumlah daun, luas daun dan bobot segar akar yang lebih besar dibanding kontrol. ABSTRACT Kailan is highly nutritious, has good prospects and is liked by the community. Kailan production is decreasing so efforts are needed to increase its production, one of which is by fertilizing. The use of inorganic fertilizers plays a role in helping the process of cultivating plants, but it needs to be balanced with organic compounds to maintain soil health. So far, fish pond wastewater has not been utilized even though it still has the opportunity to be processed into fertilizer in the form of photosynthetic bacteria. The purpose of this study was to examine the effect of urea fertilizer and photosynthetic bacteria on the growth and production components of cauliflower. The experimental design used was a factorial randomized block design (RBD). The first factor is urea fertilizer and the second factor is the dose of photosynthetic bacteria. The first factor consists of R0 = control; R1 = 5 g/polybag and R2 = 10 g/polybag. The second factor consists of B0 = 0 ml; B1 = 10 ml / 2 liters per poly bag and B2 = 20 ml / 2 l per poly bag. Each treatment was repeated three times. The interaction between urea and photosynthetic bacteria showed a significant effect only on kailan plant height. The highest kailan plants were obtained in the interaction of the R2B1 and R2B2 treatments, namely 20.14 and 19.53. The lowest kailan plants were found in the R0B1 and R1B1 treatments, namely 17.46 and 17.26. The application of urea fertilizer had no significant effect on the growth and yield of cauliflower. The application of photosynthetic bacteria significantly differed on the parameters of the number of leaves and leaf area as well as fresh weight of roots of cauliflower. The application of photosynthetic bacteria B2 (20 ml) gave a greater number of leaves, leaf area and root fresh weight than the control.