Dahlia with drooping leaves
I planted a few Dahlia on my balcony box this spring. So far so good. Then late last week as the temperature here in Toronto finally rises and becomes much sunny and higher,the leaves on the plant on the far left becomes droopy. Then the leaves of the plant in the middle also becomes droopy. I thought the plants were getting enough water so I watered it a bit more. The middle plant recovered but as you can see in this picture, all the leaves are drooping and even the stems are lumpy and not very firm. I checked the plant for insects and did not find any including signs of holes in the leaves. I planted a wooden spike and tied the plant around it to give it more support. I dogged my finger to the bottom of the balcony box and it wasn\'t wet, just moist. So I am not sure if the plant is overwatered, underwatered or suffer from a disease or insects.
Your plants may just be showing some wilt during the hottest part of the day.
Try providing some shade during the hot part of day. If your in a warm climate, morning sun and afternoon shade is best.