ellen 
I really got into using cardboard for my gardening when we were in Puerto Rico. Sadly, there isn’t any recycling on the island. I couldn’t bear tossing all the boxes we had. Some were huge ones from appliances. So, I put them to work to create my veggie and herb plots. Sheet mulching is a way to layer cardboard to suppress the grass or weeds while retaining moisture in the soil. Worms love to make their way into the moist top layer and gradually improve your soil. When it is topped with wood chips and compost, you have a perfect start to a new garden bed.
A drawback for the tropics is fire ants love the protection from the elements and often take up residence just beneath the cardboard. I suggest southern climates sprinkle diatomaceous earth under the cardboard as well as on top of the layer of mulch and compost. Diatomaceous earth is a natural product made of fossilized microorganisms that dries out and cuts up the ants. Be careful and wear a mask when applying. It is a fine dust that should not be inhaled. Using stepping stones can also save you from a swarming of ants, giving you a little bit of protection/warning before the swarm. The stepping stones will also serve as a point of reference of where they are in order to deal with the hills.
As for folks with winter, we don’t have to worry about fire ants! Yippie! Add more cardboard as the season continues to control weeds and build the soil. I have used this method in Chicago, Puerto Rico, and now out in Barrington Hills. Building up keeps the soil alive. I dig as little as possible in order to preserve the ecosystems happening below. I cannot say the same for the dogs though. they dig. In my book, all animal behavior is fair in a natural garden which is my intention here in BH. Work with nature, not against it and you will be a happier gardener.
