Q.Pea Blossom Closing
My sugar snap pea plants are growing tall and producing lots of large, green leaves. My first blossom appeared yesterday and looked great, but today I’m noticing that the blossom petals have closed. One more blossom appered which looks good, and there are a few blossom buds as well. The plant is indoors. Do you know why the first blossom has closed up? Thank you so much!

Certified GKH Gardening Expert
This happens once the stigma receives pollen. Peas will, soon, follow.
Here is an article for more information on the care of Peas in container:
https://www.gardeningknowhow.com/edible/vegetables/peas/grow-peas-in-containers.htm