Much depends on the reason her pepo squash plants poop out. If it is heat-related or drought-related, watermelons could do well in the same area but will need irrigation to help them get established in late June or early July if rain isn't falling consistently. If the pepo squash is falling prey to squash vine borers, then she might be better off planting something there that squash vine borers don't like. While it is somewhat rare to see this occur, squash vine borers sometimes do attack melon and watermelon plants.

Assuming her first frost date is sometime between mid-October and mid-November, then she should have plenty of time to get ripe melons from seed sown in late June or early July. When I sow seed sow that late, I tend to plant some of the mini watermelons, often referred to as icebox melons because they fit easily into a fridge. There are lots of great icebox melons, including Sugar Baby, Bush Sugar Baby, Yellow Doll, Yellow Baby, Tiger Baby, and New Orchid. These generally product melons in the 3 to 8-lb category, and most of them have DTMs in the 60-70 day range in our climate where there weather is hot and sunny, which they love. There's some slightly larger melons that are great too and have a slightly later DTM, like Blacktail Mountain, which produces superbly-flavored melons in the 8 to 14-lb. range in about 70-75 days (sometimes much more quickly in our climate) and Harvest Moon, a 2013 AAS winner that is similar to the heirloom Moon and Stars, but produces melons in the 10-12-lb. size category that are almost seedless. Renee's Garden Seeds has two different selections of icebox melon seeds, one with 2 types of heirloom icebox varieties, and the other with 3 icebox melon varieties. I grow both of them. Willhite Seed (located in Poolville, TX not all that far away from Decatur---but she can order from them online) usually has the seed of Sugar Baby and Crispy Critter, as well as a huge selection of watermelon varieties that produce big melons. I don't grow big melons here very often because they can take too long to produce to please me. If I was planting in her location in late June or early July, I'd stick with the icebox melons to guarantee plenty of time to get an abundant harvest.

Thanks. My friend was appreciative too. She's battling a harlequin bug infestation right now. Sounds like it's really gotten her down. They've multiplied rapidly and from what she's read, once they find you and lay a lot of eggs, they'll keep coming back. I told her about Spinosad. All the organic things she's tried have failed. She's ready to roll out the heavy artillery.