sweet peas

sweet peas

Hi... I'm a new arrival in this community and I have a question. I am planning to plant sweet peas for the first time this year. I'm going to put them on the south side of a six foot fence where they will get tons of sun. I'm thinking of simply attaching some twine to the fence for them to climb. My question: How and when to plant the seeds? Our average last frost date here (Denver, Colorado) is around mid-May. Can I plant them straight in the ground, or do I absolutely have to use pots first? Should I soak the seed before planting?
flowers in pots

flowers in pots

Helpp <3

Helpp <3

Mushroom Bed Experiment

Mushroom Bed Experiment

Garden in early Summer.

Garden in early Summer.

Blue flower ID

Blue flower ID

Need ID on Plant

Need ID on Plant