Well, why don't you find this out for yourself?

Plants are very special living organisms here on earth because they do not have to take up food to get energy for growth. Their chloroplasts can use the energy from sunlight to make sugar (food) in a process called photosynthesis. All they need is sunlight (for energy), water (which comes from rain or you have to water your plants) and carbon dioxide (from the air).

But they do need some other compounds as well like minerals and ions. Nitrogen, Potassium, Phosphorous, Magnesium are just a few of them. These compounds are normally in the soil or you can feed them to the plant (fertilizer).

Now, if you give your plant beer instead of water (beer is anyway mainly water) you may actually give the plant some of these important compounds that might help with growing. On the other hand, beer contains alcohol and this might kill some sensitive plants. This is why you have to do an experiment to find out. Make sure you buy at least two plants of the same kind. One plant has to be your control. This plant gets only water while the other plant gets beer as a water source. (You can even try other liquids like tea, coffee, sodas, etc). Make sure you buy a fast growing plant, so you can see an effect in a reasonable amount of time.

Let me know what you found out.