1 Alumni Fakultas Pertanian Universitas Gadjah Mada, Yogyakarta 2 Fakultas Pertanian Gadjah Mada, Yogyakarta Pengaruh Komposisi Media dan Kadar Nutrisi Hidroponik terhadap Pertumbuhan dan Hasil Tomat (Lycopersicon esculentum Mill.) The Influence of Media Compositions and Hydroponic Nutrient Concentrations on Growth and Yield ofTomato (Lycopersicon esculentum Mill.) Ratna Indrawati 1 , Didik Indradewa 2 , Sri Nuryani Hidayah Utami 2 ABSTRACT The research had been conducted in Mangkudranan, Margorejo, Tempel, Sleman, Yogyakarta from July2011 to January 2012. This research used split plot design with 3 replications and 20 treatmentscombination. The first factor as main plot was coirdust charcoal compositions, consisted of 0%. 33%, 50%,67%, and 100%. The second factor as submain plot was nutrient consentrations, consisted of 2 ml/liter, 5ml/liter, 10 ml/liter, and 15 ml/liter. Media compositions were analyzed namely are pH, total porosity,moisture, cation exchange capacity, electrical conductivity, C/N ratio and growth of tomato. The resultsindicated that coirdust charcoal has higher cation exchange capacity and total porosity than rice hullcharcoal so coirdust charcoal can hold and absorb more nutrients and kept them. There was not significantdifference on total fruit weight between coirdust charcoal and rice hull charcoal media, so coirdust charcoalcan be used as hydroponic media. Nutrient concentrations more than 5 ml/liter pursued tomato growth butcould increase sucrose content of tomato fruits. Keywords: composition, hydroponic, nutrient concentrations, growth and yield, tomato INTISARI Penelitian ini dilaksanakan di daerahMangkudaranan, Margorejo, Tempel, Sleman, Yogyakarta mulai Juli 2011 hingga Januari 2012. Penelitian inimenggunakan rancangan petak terbagi dengan 3 ulangan dan 20 kombinasi perlakuan. Faktor pertama sebagaipetak utama komposisi media arang serbuk sabut kelapa yaitu 0%, 33%, 50%, 67%, dan 100%. Faktor keduasebagai anak petak kadar nutrisi, yaitu 2 ml/liter, 5 ml/liter, 10 ml/liter, dan 15 ml/liter. Pada penelitian inidilakukan pengamatan terhadap media komposisi meliputi pH, porositas total, kadar lengas, kapasitaspertukaran kation, daya hantar listrik, kadar C/N pengamatan terhadap pertumbuhan tanaman tomat. Hasilpenelitian menunjukkan bahwa arang serbuk sabut kelapa memiliki pori mikro lebih banyak dibandingkandengan arang sekam sehingga kemampuan menjerap dan menahan nutrisi arang serbuk sabut kelapa lebihtinggi. Hasil bobot buah total pada media dengan penambahan arang serbuk sabut kelapa setara dengan hasilbobot buah total media arang sekam sehingga arang serbuk sabut kelapa dapat digunakan sebagai mediatanam hidroponik. Kadar nutrisi lebih dari 5 ml/liter akan menghambat pertumbuhan tanaman tomat namundapat meningkatkan kandungan gula buah tomat.