I got a big mortar / concrete mixing tub. I actually had it from mixing concrete to set 4x4 posts. It's really heavy duty and I have had it for 4 years I can't imagine any way it could crack. It's stayed out in cold and hot for 4 years... It will last forever . I think it's probably around 50 bucks for a 20 gallon volume on Amazon but cheaper probably at home Depot. it's about 30 inches by 24 inches by about 8 inches deep.. it also sits right in my garden cart perfectly so I don't have to bend over as much and tire out my back. Just a thought. If that's big enough for you it's a great option.