hi you have found the solution, leaves are curling up, most time because of heat, we say they are cupping or tacoing. Keep the roots of the plants humid and cold ( maybe digging your container into the ground or putting your container into a much bigger one filled with soil) paint the container white, put the plant in the shadow, put wet clay pepples onto the layer. just look how the roots gt a cooler envoirement. Roots dont like heat, they start dying if its to hot for them