Here is a picture of one of my baby giant pumpkins. The first leaves to come out on any plant are called cotyledons. These are the roundish ones in the picture growing on the left and right side of the plant. Notice how big they are! Most cotyledons are about the size of your fingernail. These are 3 inches across. The first true leaf is also out and is the biggest one in the picture as well as the beginning of the second one at the top of the picture. The vine will grow in the direction of the second leaf. This is good info to know as it will help you place the pumpkin in the direction you want it to grow (instead of into a fence). Notice the shape of them-they are the shape of all the rest of the leaves to come only smaller. When the leaves grow up they will be huge- 12-18 inches across! When the giant pumpkin have their first 2 true leaves, they are ready to go into the ground. Mine are ready but I’m not.
I have to partially rebuild my low tunnels that I will put the baby pumpkins in. A low tunnel is like a small hoop house only much shorter. They are meant as a temporary measure to protect the plants. I will cut them in half as I don’t think I need them to be so big this year. As soon as that happens, those puppies are going in the ground.