An experiment was conducted during Rabi season 2020–21 at the Horticulture Research Center (HRC) of Sardar Vallabhbhai Patel University of Agriculture & Technology in Modipuram, Meerut, Uttar Pradesh to assess the effect of different fermented liquid manures with RDF on growth and yield of onion. A total of ten treatment consisting T1 Control (Without Fertilization), T2 RDF( 100:50:50 ,NPK), T3 RDF + Seedling treatment with Beejamrit @ 6%, T4 RDF + Seedling Treatment with Beejamrit @8%, T5 RDF + Foliar spray of Jeevamrit @ 6%, T6 RDF +Foliar spray of Jeevamrit @ 8 %, T7 RDF + Seedling treatment with Beejamrit @6 %+ Foliar spray of Jeevamrit@6%, T8 RDF + Seedling treatment with Beejamrit @6%+ Foliar spray of Jeevamrit @8%, T9 RDF + Seedling treatment with Beejamrit @8%+ Foliar spray of Jeevamrit @6% and T10 RDF + Seedling treatment with Beejamrit @ 8%+ Foliar spray of Jeevamrit @8% were taken for the study. Among the treatments, plants fertilized and treated with RDF + Beejamrit @ 8%+ Foliar spray of Jeevamrit @ 8% showed superiority in terms of growth parameters while bulb yield parameter demonstrates superiority when plants treated with RDF and seedling treated with Beejamrit @8% with foliar spray of Jeevamrit @ 6% over other treatments.