We have two futon mattresses on the floor, since it's the safest way to sleep for babies (there's nowhere for them to fall if they are already on the floor!). (parents.today.com)
You can also purchase organic futon mattress covers that are made especially for futons. (best-mattress-reviews.com)
They include The Savvy Rest natural latex mattress, Lifekind OrganicPedic natural rubber mattress, Green Sleep natural rubber mattress, Soaring Heart Futon mattress, Eseentia, and Natura Eco-Haven. (best-mattress-reviews.com)