Southwest Yard and Garden shows viewers how to prepare the soil in order to plant Irises. You can see if your oil needs to be prepared because it would look like it need nutrients. Irises deplete the oil they are in so you need to restore their nutrients to the soil. First, you should get your soil tested to see what nutrient should be added to the soil. First loosen the soil. Next, add in the nutrients. Start with alfalfa pellets to add Nitrogen. Add a little bit of sand to loosen soil - don't add too much! Next, add humus and manure to the soil. Also add some cotton-bur compost to help the soil add water and then gypsum to help plants use all that you have added. Now, rake the additives and mix them into the soil. Make it smooth and plant your irises!