Purpose Faecal sludge (FS) has been co-composted with many organic solid wastes globally. Agricultural wastes, such as oil palm empty fruit bunches (EFB) and cocoa pod husks (CPH), have received very little research attention as far as combining with FS is concerned. This study aimed at co-composting these wastes at different ratios to produce safe compost for use as soilless medium for raising tomato transplants. Methods Dewatered FS (DFS) was mixed with shredded EFB and CPH at five different ratios: 1DFS:1EFB, 1DFS:1CPH, and DFS:EFB:CPH in ratios of 1:1:1, 2:1:1, and 2:2:1 and composted for 3 months. Select physicochemical parameters and pathogens were monitored every fortnightly and 3 weeks, respectively. Results Maximum temperatures obtained ranged 46.8–54.5 °C. Though these temperatures were lower than sanitizing temperatures prescribed by USEPA, no E. coli was found in any of the piles at the end of composting. The ratio 2DFS:2EFB:1CPH was found to be the safest formulation and hence was used to grow tomato under greenhouse conditions. Tomato seeds were sown in three different growing media: 100% FS-based compost, 100% rice husk biochar, and 50% FS-based compost–50% rice husk biochar mix. Conclusion Results showed that FS-based compost was a suitable growing medium for tomato. Further studies into the optimal rate and frequency of application of compost teas on tomato are recommended.

The medium from which seedlings are transplanted influences seedling growth and survival on the field. The objective of the experiment was to compare how growing media affect the growth and survival of cocoa seedlings under field conditions. The seedlings were raised in both soil and soilless media and were transplanted on the field in June, when they were six months old. The experimental design was a randomized complete block design with three different growing media: 1. top soil, 2. sawdust + poultry manure + rice husk biochar (70%:25%:5%), and 3. sawdust + poultry manure + municipal solid waste compost (50%:35%:15%). The cocoa seedlings were transplanted at a spacing of 3 m × 3 m at 12 plants per plot and each plot size measured 45 m × 45 m. Data were collected on plant height, leaf number, stem girth, leaf chlorophyll content, percentage of plants that shed their leaves, and percentage of survival. Results indicated that seedling survival at the onset and end of the dry season was significantly (P < 0.05) higher for seedlings transplanted from soilless media compared to those from the top soil treatment. Irrigation will be necessary to maintain high seedling survival when seedlings are transplanted from the top soil for a well-established plantation.

Cocoa (Theobroma cacao) seedlings are very sensitive to water stress during the nursery stage and early field establishment. Sawdust, carbonated rice husk, and compost in the following ratios (i) 60: 40: 0 – M1, (ii) 60: 30: 10 – M2, (iii) 60: 20: 20 – M3, (iv) 60: 10: 30 – M4, (v) 60: 0: 40 – M5, and (vi) topsoil – M6 as control were used to investigate the effect of growing media, water stress, and re-watering on the growth, dry matter production, and partitioning of cocoa seedlings. Each combination was subjected to water stress 6 weeks after sowing for a period of 4 weeks, after which they were rewatered. Plant height, stem girth, leaf number and area, and seedling biomass were significantly higher in soilless potting media as compared to topsoil. M4 and M5 significantly recorded the highest total dry weight, plant height, stem girth, leaf number, leaf area, and root volume before imposition of water stress. Following imposition of water stress, cocoa seedlings grown in M4 and M5 showed a recovery that was superior to the other growing media, indicating that higher proportions of compost together with sawdust and carbonated rice husk provide an alternative for growing cocoa seedlings.