Bales may be either wrapped or bagged. Wrapping requires special equipment, but the cost of the plastic is less than bags. Thus, wrapping is more economical than bags for large quantities of balage, while bagging is more economical when fewer bales will be made. Plastic for wrapping should be at least 4 mm thick and should have UV inhibitors if white to reduce rate of plastic breakdown. Bales should generally be wrapped with at least two layers of plastic to ensure airtight wrapping and reduce the potential for holes.
Bags come in a variety of sizes and thickness .
Black bags tend to weather better than white bags, but silage may become hot in high temperatures. White bags have been improved with ultra-violet inhibitors which stop light from breaking down the plastic. Reusing bags is not normally recommended. Bags should fit bales snugly, but should be big enough to slip over the bales without difficulty. Forage baled at 60 percent moisture or higher can not be made into six-foot size bales because they would weigh too much for many round balers.