In zone 7 your last frost date will be around May 15th but your going to want the soil temperature to be above 60 degrees Fahrenheit ideally between 70 - 95 degrees if you lay down black plastic this would speed the process of warming the soil. What I like to do is go backwards using the days to maturity on the seed packets which are normally 90 - 120 days. Your first day of frost seems to be end of September to middle of October depending where you are. To sum it up, end of May beginning of June is when you should plant.

Thanks for the input...seems awfully late to me though (by the end of May it's like 90 degrees even in the north!) I got other advice putting the planting date between April 15 and May 15, and since we've had such an amazingly warm winter, we have no clue when it will (or IF it will) even get really cold...I think we are going to go with a staggered schedule...plant some April 15 and each couple of weeks thereafter, just to find out which time frame works best--there are plenty of seeds from the last crop in KY! :) What do you guys think--anyone tried this?

We have staggered plantings as a means of finding the best time to plant, and have lost some of the early seeds in doing that. However, the later plantings have usually done better for us. Keep in mind, we are in the zone 5b/6a grey area. AND, my husband has dreams that every seed will come up and produce at least a dozen wonderful gourds............
So, I would advise you to check with your area Master Gardeners, or the local county Extension Service for best planting times.
And then again, do your own testing. You have your own seed and you won't be out much, right?
You won't know if you don't try!

Jan