The phrase "spring in" can have several synonyms based on its context. In gardening and landscaping, "plant" or "seed" may be used interchangeably. In relation to energy or motion, "propel" or "launch" may be more appropriate synonyms. For rebounding or bouncing back, "rebound" or "bounce back" could be used instead. "Jumpstart" or "revitalize" may work if referring to starting something off on the right foot. In regards to pointing out something new or fresh, "introduce" or "usher in" may be used instead. Overall, the synonyms for "spring in" can vary based on the situation, but it's important to choose the right one for a specific context.