太阳花种子 can be found when harvesting 太阳花 while it is blooming. As its name implies, Daybloom will only bloom during daytime, showing off a sunflower-like head. At this time it will drop 1-3 Daybloom Seeds.
Daybloom Seeds can be placed in empty 粘土盆s or planted on pure or hallowed 草 and grown into additional, harvestable Daybloom. Potted Daybloom will grow anywhere, even indoors and not in direct sunlight, but is slow to mature, because it only grows during daytime hours. Use a Pickaxe and left-click on the flower or herb above the Clay Pot to harvest it.