what is it? Location? south north etc. still green so probably okay.

Water with a pinch of 20-20-20 fertilizer. Stat!

Yes, supposedly you are not to "feed" a thirsty plant. Water first then next day give some fertilizer.

Thank you I watered with some fertilizer and told them I would never leave them for 5 days again!
My husband fessed up.. He thought the rain we've had in upstate NY was enough. Poor lil fellah's! Thanks again!

Aww poor things looks like being under the verandah didn't suit them for the rain you got...

Hanging plants dry out faster than other potted plants. In the future if you plan to leave them for more than a day, you can hire your neighbor's kid to water them or you can get one of those extended watering globes like these: http://www.gardeners.com/buy/aquacone-watering-device/18034.html?start=3&q=watering%20spikes

In the future, if you do your own planting in the hanging baskets, you can buy stuff that is added to the soil to make it absorb more water so they don't dry out so quickly. Like this: http://www.gardeners.com/buy/terra-sorb-drought-proofing-crystals/14091.html

They also make "self-watering" planters that have a reservoir you can fill with water. http://www.gardeners.com/buy/self-watering-hanging-baskets/34-368.html?start=1&q=self%20watering

Dead heading is needed for most petunias and if yours perk back up and you deadhead them you should have more beautiful blossoms in about three days.