When is the general guideline for transplanting seedlings after they have developed?

Transplanting seedlings at the stage when the first true leaves have developed is considered the ideal time because it indicates that the seedlings are mature enough to survive and thrive in a new environment. True leaves are the second set of leaves that form after the initial seed leaves (cotyledons) and are a sign of healthy growth and root development. At this stage, the seedlings have typically established a sufficient root system that can support their growth when moved to a larger pot or garden bed.

Transplanting too early, such as immediately after sprouting, may not provide the seedlings sufficient time to develop the necessary root structure to handle the stress of transplantation. If seedlings are transplanted when they are 6 inches tall, they may have already experienced stunted growth due to being crowded or lacking nutrients. Waiting for plants to begin flowering before transplanting is also not advisable, as the stress of transplanting can further delay growth and flowering, making it less effective for the plant's overall health.