Final answer:
The small eggs/seeds found in the substrate of the Calathea plant may not be plant seeds. They could potentially be animal eggs, which is a common way for insects and other organisms to ensure the survival of their offspring. Consult an expert for proper identification and guidance.
Step-by-step explanation:
Based on the description you provided, it is unlikely that the small eggs/seeds you found in the substrate of the Calathea plant are actual plant seeds. Calathea seeds usually have a distinct appearance which differs from what you described. Additionally, plant seeds do not typically have a crusty texture.
Considering the characteristics you mentioned, it is possible that the small eggs/seeds you found could be animal eggs. It is common for insects and other organisms to lay their eggs in the soil or substrate of plants as a means of protection and providing a food source for their offspring. Without further information or visual identification, it is difficult to determine the exact species of the eggs. If you are concerned about pests or potential damage to your plant, it would be advisable to consult a local botanist or pest expert who can properly identify the eggs and provide appropriate guidance.