They look like they're in containers? If so, they need to keep a certain amount of moisture in the soil at all times. If the soil completely dries out, it's not good for the plants or the soil.

This is just what works for me, but my containers with fast draining soil need water every morning and I keep them out of direct sun in the middle of the day after March. I keep them on drip systems that run for 8-10 mins in the morning.

I have other containers that have a more permanent soil mixture that doesn't need water every day but they are large and the soil is more compact.

Thank you IandyAZ! I believe you are right. In fear of over watering I was under watering. The vincas have been doing a little better with watering 1-2 x per day. The Marigolds are goners. I just planted Marigolds seeds in planters hopefully they take. I will remember to move them midday. I appreciate your feedback. Thank you!!