The use of chicken manure and its liquid derivative, chicken manure tea, is widespread among horticultural farmers in Kenya due to its perceived rapid stimulation of plant growth compared to synthetic fertilizers. However, these claims lack sufficient scientific backing. Recently, chicken manure tea has gained preference over solid manure, partly due to the presence of wood shavings in the latter. To evaluate their effectiveness, a study was conducted on cabbage (Brassica oleracea var. capitata ‘Quiser F1’) under polytunnel conditions using four treatments: chicken manure, chicken manure tea, a combination of both, and NPK fertilizer (as a control). Seedlings were transplanted into 10-liter containers in a randomized complete block design with four replications. Data collected included soil and tissue mineral content, soil pH, vegetative growth parameters (stem length, leaf width and length, number of leaves), and marketable head yield. Statistical analysis was performed using R, with means separated via Tukey's test at α ≤ 5%. Results showed that all organic treatments, particularly the combination of manure and tea, significantly enhanced early-stage growth, though these effects waned in later stages. Tissue nutrient content was lowest in the combined treatment, possibly due to increased microbial activity and nutrient immobilization from excess organic matter. Despite this, it produced the largest marketable heads. The findings suggest that chicken manure, in all forms, can potentially substitute synthetic fertilizers in cabbage production. However, further field-based studies are needed to confirm these results.