Organic tomato transplant production in compost-amended substrate

There is limited information available about organic fertilization of vegetable transplants. The availability and release of the mineral nutrients from organic fertilizers is not fully understood. The objective of this study was to determine the effect of compost rate and chicken manure on the growth of tomato transplants. Tomato transplants were grown in an organic peat-based substrate (Garden Safe (R) Organic Potting Mix) amended with six rates of either compost (0% to 50%, by weight) or chicken manure (0% to 40%, by weight). The results showed that plant dry weight was minimally affected by compost rates, suggesting that compost provided only a minimal amount of nutrients to the plants. However, since transplants produced with compost-amended substrate were of similar quality compared to those produced exclusively with the substrate, it suggests that compost may be used to partially replace peat-based substrates used for transplant production. Shoot, root and plant dry weight increased with increasing rates of chicken manure (applied prior to seeding) reaching a maximum at 10%-20% (by weight) and then declined at 40% rate. Thus, chicken manure mixed with the substrate appeared to provide enough nutrients to tomato transplants.