Abstract: With an increasing trend towards organic agriculture, the use of organic compost is becoming a necessity. Organic compost fertilizer produced from agricultural waste generally contains low nutrient contents essential to plant growth. Improving the quality of organic compost fertilizer will help farmers raise healthier food while promoting safer environment. The study aimed to investigate the effect of green biomass in enhancing the quality of compost from crop residues. The study used experimental research method laid out in Completely Randomized Design (CRD) in three replicates. Treatments were increasing volume of mixture of green biomasses of Leucaena leucocephala (Lam.) de Wit, Tithonia diversifolia (Hemsl.) A. Gray, and Moringa oleifera Lam. added to pre-composted crop residue. Wood ash comprising 1% by weight of dry compost materials was added per treatment. The macro and micronutrient content of finished compost were analyzed. Finished compost quality in terms of Nitrogen, Phosphorous and Potassium were significantly increased by enriching pre-composted crop residue with increasing volume of mixture of green biomasses. The best treatment combinations were mixing pre-composted crop residue and mixture of green biomass at 3:5, 3:4 and 3:3 in that order. The micronutrients particularly Zinc and Iron were also significantly increased while Copper and Manganese were significantly lowered. The organic Carbon content of finished compost was significantly increased while the pH levels were enhanced towards neutral level.