"Going to seed" typically describes a condition where a plant has matured beyond its usefulness or attractiveness, and has begun to produce seeds. However, the opposite would be when the plant is flourishing or thriving in its prime state. Antonyms for "went to seed" might include terms like thriving, flourishing, prospering, prosperously, blossoming, blooming, budding, or thriving. These terms describe the opposite condition of decline, showing that the plant is still growing and producing new growth or flowers, rather than beginning to look ragged or worn out. Ultimately, the antonyms of "went to seed" all highlight a sense of vibrancy and health, showing that the plant is still in its prime state of being.