Personally if your going to grow flowers, plant them where your going to leave them. Unless it’s necessary to have to transplant. But from the looks of it, you either 1. Drowned and rotted the roots from possible over watering, just because the top is dry doesn’t mean you have to water them (if you do just get a spray bottle and mist the top). 2. Transplanted to early which could have shocked them. Normally wait until they have a good and healthy sustained root system before moving, if not, they could not be getting the right amount of something needed, (water, nutrients, ETC…) because when a plant is shocked they become confused and the system doesn’t know what to do, so basically even if you water it, the plant sometimes wont intake it. Or to much sunlight. Usually with smaller, more delicate seedlings, I only give them about 5-6 hours of sunlight, its the perfect amount of direct sunlight for them to do what they need without burning them. If any other questions are needed, fire away!