The effect of caffeine on plant growth has been studied time after time. There are many people who believe that the use of caffeine can help plants to grow at a higher rate of speed. Of course, there are many others who think that this is a myth, and all in all, a waste of good caffeine. While there is still not definitive answer to this question, there are some theories that seem to be getting close to finding a final answer.
On one side of the argument, there are those who feel that adding caffeine to a plant will help it to grow faster. This has been studied time after time, but at this point it is difficult to determine whether the caffeine is at work, or if the beneficial matter is something alongside such as potassium. In other words, caffeine may help in this area but it is hard to say if this is the case if this is not the only substance being used.
The other side of the argument is that caffeine can retard the growth of plants. Once again, experiments consist of using pop or coffee in order to test the results. The issue with this is that other ingredients may also effect how the plant grows. So even though it may be possible that the caffeine is slowing down the growth of the plant, it could be another ingredient that is causing problems as well. Some have found that adding coffee to a plant helps it to grow faster than if using water alone. But again, this may be the case because of the potassium and phosphorous that is also included.
It is difficult to determine the exact effect of caffeine on plant growth. There are two schools of thought, and until further testing is done, there will be no definitive answer.