A short drain hose can affect the whole performance of your dishwasher. It will not remove the dirty water efficiently. The good news is that you can extend it to your desired length. To do this, look for a flexible hose compatible with your dishwasher's current drain hose. You can find it in a drain hose extension kit with a 3ft dishwasher drain hose extension. Connect the dishwasher hose extension with the drain hose and check for any leaks. If you need help doing this, a qualified plumber or service technician can come through for you.