Answer: Without knowing how long they will need to keep the plants it is a bit difficult to make a suggestion. In my experience, sunflowers do very well started in peat pots, the seeds are large enough for small children to handle easily, they germinate fast and can be transplanted quickly. For a longer term project, they might use marigold seeds or even cherry tomato seeds. Sicne they need use only a few seeds per pot, the cost should be pretty reasonable no matter what you select.
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