Christina and Patrick came for several weekends to help pour and smooth the earthen floor. I used a grid of redwood to level the floor and we smoothed it in 1/2" layers, to prevent cracking. The mixture is mortar sand with just enough clay to bind it together. Too much clay makes too much cracking. Chopped straw was used only in the very top layer for decoration. In the floor, sand is needed for strength and drainage. Straw is not needed.