Question
Mine is growing so big how do I keep it in the house. The leaves are drooping over and it is tall I have it on a file cabinet. Do I repot it? I live in Northwest Indiana. Michigan City.       Also,  How can I kill poison ivy. Thanks I can use the information.

Answer
Rose,
You can prune them back over a period of time to reduce their size. Type "peace lily pruning" into your search engine to see how it is done. Do not repot it into a larger pot. It will just grow larger. You could divide it into more than one plant and repot them.
Water your peace lily in the following manner. I water most of my plants this way. Check how much the plant weighs when thoroughly watered VS its' weight when it is ready to be watered again. Sometimes it helps to put a saucer under the pot and let the plant sit in water for 10-15 minutes. After that pour off the excess water. Pick the pot up ( or lean it if it a large pot ) and feel how heavy it is after watering it thoroughly. Don't water it again until it feels considerably lighter and the top of the soil is light in color. Mother Nature doesn't water once a week/ month/ etc. ...Depending on plant types, sunlight exposure and pot size plants will need water at many different rates from once a day to once a month or more. You should turn the plant a 1/4 turn once per week to keep the growth even. Plants do need to be fertilized every month or so during their active growing period to stay healthy...
They do not like direct sunlight unless it is morning sun...Peace lilies will show signs of wilting if you let them go too dry between waterings...Spray misting the foliage 1-2 times per week will help stop yellowing and drying of the leaves...  
Remove yellow leaves when they become unsightly...
Hope this helps.  
Rick in Southern NJ