That watering trough sounds awesome! I go to a place called the Dirt Exchange in Ballard, WA. They sell self-service u-load soils, compost, etc., with a 1/2 CY minimum order. I'd use their Vegetable Garden Mix at $58.50 per CY, with 300 gallons being a bit under 1.5 CY, so maybe $75-$80 for...