Tell us where you are ? what has your weather been/is ?(rain, temperatures, sun...), How often do you water, fertilize them , are they in the ground, container, raised bed , what kind of soil they are in ? ? ?

Without knowing any of the above, as I look at the picture, the things that pop up in mind is" SUN SCALD, .. TOO MUCH WATER ,... TOO LITTLE NUTRIENTS.

Once you provide additional info, then others can also comment constructively, rather than by guessing game.

Now the ball is in your court.