I have clay soil too - my bush beans are okay since I dug about 6 inches down mixed the clay with some compost/clay soil amender and made about a 2 in raised bed. I only have 6 plants and I get about a serving's worth per plant every other week. It's not much, but I also started wayyy late :D
Well the odd part is that the watermelons are still growing well, but it was only the honeydews that stopped. I've pinched off the tips and I will hold back on watering the honeydews. I have clay soil and have only amended about 8 inches below the ground level - so including the raised bed...
I have two types of melons growing: Honeydew (apparently) and watermelons.
The honeydews started fruiting first, 2 melons per vine, watermelons only recently. The honeydews have STOPPED growing in size though I've maintained a consistent watering schedule and the weather is still good (70-85...