What if you grow watermelons on concrete? Do they sometimes get squishy? Also, what soil or mixture is best for a garden? I heard from my mom that rotten chicken poop is the BEST, but only when they are about full size.
Certified GKH Gardening Expert
To keep them from becoming mushy or moist, you should place the watermelons on newspaper, cardboard, or a bed of straw.
As for chicken manure, this is best used when composted. This article will help: https://www.gardeningknowhow.com/composting/manures/chicken-manure-fertilizer.htm