What growing zone are you in? Where I live, snap peas are a cool season crop and don't do well this time of year.

Mine look like that too. I've just started getting a nice amount of peas but the plants look crummy. They did this last year as well. I didn't know they were a cool season crop. :)

The kids picked out seedlings last spring at the hardware store and we just planted them not knowing a thing about them--this year's are seeded from those. Maybe I'll plant more when it cools off and see how it goes. (I'm in zone 10.)

Zone 7. does the yellow bottom mean they are dying?

You can't do anything, except maybe make sure they are watered. Don't give up yet, Peas don't like the heat, but they should produce some snaps even if the plants start to look ugly, you have flowers. Pea plants die in summer heat, it is inevitable.

I try to plant them in mid March to get an early start in Ohio, but they don't really grow much until it gets mildly warm in May. Then I hope I get snap peas by mid June, because the plants decline rapidly by late June.

Neal, zone 7 here, and I got my sugar snap seeds planted late, too. They are filled with both blooms and snaps, and the bottoms near the earth were slightly yellowish awhile back. I gave them a few doses of organic fertilizer and they've greened up. Yes, it's hot here, 95 F yesterday, but are producing well. I use a Drip line, or ground water carefully, daily when it doesn't rain.