The Case for Wool on a Latex Mattress
Wool and latex share similar properties, so they accompany each other well on a mattress. They both won’t mildew, won’t harbor dust mites, are breathable, flexible and are good at distributing heat so you don’t end up too cold or too hot.
In a latex mattress, wool has another purpose as well as a comfort layer. It is an excellent protector of the latex. Latex is biodegradable; you can throw it in your compost pile when you are done with it. A few months later, it will be completely crumbled. Wool is not as biodegradable; you can weave it into garden mats to keep down the weeds and it will take 2 years for it to degrade rather than a few months. Natural latex contains an antioxidant, much like vitamin A is in our foods. Once the antioxidant dissipates, the latex can be affected by oxygen. Direct sunlight, direct heat (as from a vent) and poor air quality can cause the latex to yellow and harden sooner than otherwise. Since latex is biodegradable, it appreciates being wrapped to keep it from the elements that cause it to prematurely harden. Thus, the dense wool wrap adds a breathable layer of defense against the elements.
Some DIYers like to wrap their natural latex slabs with a batt of wool, some just like the quilted ticking with wool inside it. While a second cotton case would alternatively protect the latex, cotton just is not as nice of a fiber as wool. Also, a carded wool batt is more affordable than cotton fabric being a less processed fiber.